Paris and Capulet's discussion of Juliet's age in the beginning of this scene continues another of the play's resounding themes: youth versus old age. In the world of the feud, the older generation's conflicts and bids for power control the destinies of their children without much apparent thought for their children's ultimate welfare. Thus the flaws in this patriarchal system make Romeo and Juliet's waywardness in love seem all the more innocent.
Capulet worries that Juliet, at 13, is too young to be married. He cautiously advises Paris: "Let two more summers wither in their pride / Ere we may think her ripe to be a bride." Shakespeare's emphasis on Juliet as a teenage girl poised between childhood and adulthood highlights that Juliet is a very young tragic heroine who is forced to mature extremely quickly during the course of the play.
Although Juliet's parents, like Romeo's, seem to look out for their child's best interests, Juliet's position is clearly subordinate to her father's political concerns. In the discussion of her marriage, Juliet is primarily a commodity. Paris wants her mainly because of her social status and beauty. Capulet may even be using her youth and innocence as "selling points" to Paris rather than expressing genuine fatherly concern for protecting her from the corruption of the big wide world. No sooner does he insist that Paris win Juliet's consent than he arranges the feast where Paris may woo her more easily.
Her father's half-hearted nod to gaining her consent is the last evidence of Juliet being empowered by her family. Hereafter, fate and her family control the marionette strings. Her actions (although not her words) are contrary to the powers that try to control her. Although her defiance doesn't become manifest until she refuses to marry Paris, this passage is both the twilight of her permissive independence and a harbinger of her defiant independence.
