Through Romeo's actions in Act 3 Scene 3, it can be judged that this is typical of Romeo to act in this way. From the start of the play, Romeo shows his adolescent behaviour by the way he acts. In the first act of the play, Montague says what Romeo does after being refused by Rosaline. He;
"Shuts up his windows, locks fair daylight out
And makes himself an artificial light"
After being denied sex with Rosaline, Romeo hides himself away and acts exactly like the stereotypical teenager would in the same situation. Romeo further enforces this view when talking to Benvolio. Romeo likes the idea of being a lover, and not the actually loving itself. He uses a series of oxymorons to compare love to hate.
"Feather of lead, bright smoke, cold fire, sick health"
The use of oxymorons here illustrates Romeo's confusion emotionally. While he believes that he is in love, he finds it painful and traumatic. The only reason Romeo is hurt is because Rosaline won't have sex with him - Romeo's relationship with her is not love, only lust. Romeo tells Benvolio that;
"She will not stay the siege of loving terms,
Nor bide th' encounter of assailing eyes,
Nor ope her lap to saint seducing gold"
Here, Romeo tells Benvolio that after trying to bed Rosaline with affectionate words ("siege of loving terms"), he even tried to pay her gold that, Romeo's says, would even seduce a saint. Here is a clear sign that Romeo clearly is only with Rosaline for sex and, as Rosaline won't consummate their relationship, Romeo becomes depressed. This is the same as Act 3 Scene 3 where Romeo is distraught over having to leave Verona - he may have married Juliet, but as with Rosaline he may've just been doing it because he thought he was in love.
Romeo's impulsive behaviour is also typical throughout the rest of the play. When with Friar Laurence in Act 3 Scene 3, Romeo doesn't think things through. He automatically feels sorry for himself and his only solution to the problem is to kill himself. His impulsive nature is apparent in many different sections of the play. Firstly he gatecrashes the Capulet party to try and find Rosaline, and then he marries Juliet soon after meeting her. One of the signs of maturity is the ability to not act on impulse and to think matters through. When Romeo first sees Juliet at the Capulet party, he instantly falls in 'love' with her. Yet Romeo hasn't even talked to Juliet - it's a sign that Romeo is acting on lust rather than true love, as is shown when Romeo says;
"O she doth tech the torches to burn bright!
...Beauty too rich to use, for earth too dear"
Nonetheless, Romeo proposes to Juliet and arranges Friar Laurence to wed them.
Another example of Romeo's impulsiveness occurs after the death of his friend Mercutio. He blames Juliet for making him too feminine;
"O sweet Juliet
Thy beauty hath made me effeminate,
And in my temper softened valour's steel"
He wants to fight, yet because of his feelings for Juliet he appears to be calmer and more mature. Yet Romeo hasn't changed. He desires revenge against Tybalt for murdering his friend, and he says that he must now rely on his anger;
"..fire eyed fury be my (Romeo's) conduct now"
He then goes to fight, and ultimately kill, Tybalt. Though it seemed Romeo had become more mature after marrying Juliet, he still acts on his impulses rather than to think out situations. This is typical of him in Act 3 Scene 3, where is feels depressed and wants to die.
A further example of Romeo's adolescent behaviour is towards the end of the play. When Romeo hears of Juliet's apparent death from his friend Balthasar, he instantly decides he should kill himself, which is apparent when Romeo says;
"Well, Juliet, I will lie with thee tonight"
He doesn't go to visit anyone beforehand - Friar Laurence, Benvolio or anyone else. He heads straight to the apothecary, buys the poison and goes to kill himself. He also killed the County Paris who was there to mourn Juliet's death. Romeo tells Paris that he doesn't want to fight him;
"I beseech thee, youth,
Put not another sin on my head
By urging me to fury.
... I come hither armed against myself"
However, Romeo succumbs to his temper and kills Paris. He didn't need to fight Paris as Romeo wanted to die anyway. The County Paris was only trying to defend Juliet from her 'enemy', the Montagues. Romeo let his anger overcome him. Romeo finally takes the poison and dies. This is another typical characteristic of Romeo, which is portrayed in Act 3 Scene 3. Through his dismay of being banished from Verona, he doesn't seek advice or a solution to the problem. He immediately sinks into a depression and takes an overly pessimistic view of the situation.
On the other hand, Romeo's actions towards his banishment may be something other than immaturity. Although not commonly known today, Romeo is only a teenager and typically he acts just like anyone else his age. Perhaps his love for Juliet is dramatised, but Romeo is acting like the in-love teenager would. He may have constant mood swings, but this may because of all the events that occur around him. At the start he was in love with Rosaline, but then they broke up. Then he married Juliet, but then Mercutio was murdered, Romeo killed Tybalt, Romeo was banished and Juliet died. In the middle of all this love, hate and violence it is understandable why Romeo behaves the way he does. In this sort of situation a mature adult would have a hard time coping, yet Romeo is only a teenager - trying to handle everything that's happened is too much for him, therefore he resorts to his angry tirades. Romeo at times seems like a mature man, such as when he tries to reason with Juliet's cousin, Tybalt;
"I (Romeo) do protest I never injur'd thee,
But love thee better than thou canst devise"
He tries to make peace with Tybalt, but ends up killing Mercutio, which in turn leads to Romeo killing Tybalt. Romeo also tries to make peace with the County Paris;
"I love thee better than myself.
... Stay not, be gone: live"
Here, Romeo desperately wishes not to fight the County Paris, yet through Paris' threats he is forced to do so. Through these examples it seems as though Act 3 Scene 3 is not representative of Romeo's actions throughout the play, as he can be a mature man.
Other than his maturity, he also shows great amounts of love throughout the story. Although his relationship with Rosaline was mostly based on lust, Romeo still feels great sadness for losing her and even goes to gate crash the Capulet party to try and get her back. Then there is also his love for Juliet, which he expresses by sneaking into the Capulet residence and declaring his love in the famous balcony scene. He proposes to her and marries her the next day, which shows his commitment to her. Here he seems like a thoughtful and affectionate young man. He also says that he loves two people he should hate - Tybalt and the County Paris;
(to Tybalt) "love thee better than thou canst devise"
(to the County Paris) "I love thee better than myself"
Although pressured by his family and friends to hate all Capulets, Romeo still can love two of his enemies. His love for Juliet has given him a new perspective on the world. This is in complete contrast to the way Romeo acts in Act 3 Scene 3, where he is melodramatic and depressed.
In addition, other people have good things to say about Romeo. Near the beginning of the play where Romeo and friends sneak their way into the Capulet's party, he is seen by Tybalt. When he tells Capulet, he says;
"Verona brags of him
To be a virtuous and well govern'd youth.
I would not
... do him disparagement"
The head of the family he is an enemy with is praising Romeo. This shows he has a good reputation in Verona, as he is well mannered. Verona boasts about him for being such a good young man. Also, another man who likes Romeo is Friar Laurence. The Friar always has time for Romeo, whether it is for advice or just to help him. Although the Friar does sometimes get angry with Romeo, such as when Romeo is banished, he always has advice for him and is always willing to help Romeo when he can.
In conclusion, Act 3 Scene 3 both is and isn't representative of Romeo's behaviour throughout the play. Romeo often does act like an immature teenager, who often happens when something major happens around Romeo - such as violence and denied love. Romeo often cannot control his feelings and becomes manically depressed or violent. When Mercutio is killed, Romeo immediately seeks revenge and kills Tybalt. He becomes depressed at having to leave Verona for his crime, and also decides to kill himself when he hears that Juliet is dead. He doesn't stop to consider his options at any of these points, but he acts on his impulse and often makes things worse.
On the other hand, Romeo often tries to find peaceful solutions to his problems, such as when Tybalt comes to fight him. Romeo tries to be reasonable, but Tybalt kills his friend and Romeo, being only a teenager, is filled with anger and so gets his revenge. Also with the County Paris, Romeo implores him to leave as he does not wish to fight, yet Paris does not listen and Romeo is forced to defend himself.
Ultimately, while Romeo is thought to be a well-mannered youth by the majority of the town, that decision is made from Romeo's actions before the play is set. This is before Romeo becomes broken-hearted by Rosaline, and is infatuated with Juliet. During the play itself, Act 3 Scene 3 is mostly typical of Romeo's behaviour throughout. Although for some parts Romeo conducts himself in a more mature manner, he mostly acts exactly what he is - a love struck teenager.