What is Romeo's age?
Romeo's age is not given in the play, but there are many hints he is a teenager. First, Juliet, his beloved, is not quite 14. Second, Paris, the man Juliet's father betroths her to, is older and established, so at least 25. Romeo seems to be younger than his rival, so probably no more than 20.
Romeo, like Juliet, still lives in his father's house and doesn't seem to have any sort of career or responsibilities. His father worries as the play opens because Romeo is up all night mooning about over Rosaline. This makes Romeo sound very much like a teenager.
Romeo's impulsiveness also seems very characteristic of a teenager. He hasn't yet learned to take the long view. He simply doesn't, for example, want to wait for marriage to Juliet. Instead, he wants to marry her the day after meeting her. A more mature individual would probably want to get to know his prospective mate a little better before rushing headlong into marriage.