Romeo is initially portrayed as a young whiny teenager. When the reader first meets Romeo, he is lamenting over the fact that Rosaline does not reciprocate his love. Shakespeare introduces Romeo as a young, heartbroken teenager. As the play continues, though, we see that Romeo's affections are easily diverted by Juliet, who Romeo instantly falls in love with. There are some other keys to Romeo's presentation. He is not close to his family. His parents are barely even in the play. He seeks advice from Friar Laurence, and not his parents. Romeo is very willing to throw away his family name for Juliet.
Juliet is also portrayed as a young teenager. While the reader does not know how old Romeo is, we are told that Juliet is 13 years old. She is loved by her parents and respects her parents' authority . . . at first. Lady Capulet tells Juliet to keep an open mind about Paris, and Juliet agrees. Then she meets Romeo and instantly falls in love. From that point forward Juliet is rather rebellious against her parents' wishes.
The presentation of Romeo, Juliet, and their relationship exports and reinforces several basic myths (beliefs and values) of culture.
First, true love exists.
Second, love at first sight is possible. Their love for each other can't initially be based on their conversation skills. They kiss after just 14 lines of dialogue.
Third, people do some crazy things when they are in love. Juliet spurns her parents. Romeo risks banishment. Juliet contemplates suicide. They get married after 2–3 days of knowing each other. They kill themselves.
Fourth, young people/teenagers can be quite impetuous and emotional.
Fifth, young love is best. Shakespeare wrote about teenagers, not Mr. and Mrs. Montague.