In William Shakespeare's play "Romeo and Juliet," Romeo and Juliet were very young when they got married. Juliet's age is explicitly mentioned in the play, as she is just about to turn 14 years old. Romeo's exact age is not specified, but he is portrayed as being of a similar age to Juliet.
As for how they managed to get married without their parents knowing, their marriage takes place in secret with the help of Friar Laurence. The events leading up to their secret marriage are as follows:
Romeo and Juliet meet and fall in love at a party hosted by the Capulets, Juliet's family's rival faction. Despite the feud between their families, they are immediately drawn to each other.
They decide to get married in secret, as they are aware that their families would never approve of their union due to the ongoing feud.
They seek the help of Friar Laurence, who is a trusted confidant to both Romeo and Juliet. The Friar agrees to marry them, hoping that their union might help bring peace to their families.
In Act 2, Scene 6, Romeo and Juliet meet Friar Laurence in his cell, and he performs the marriage ceremony for them.
The marriage remains unknown to their parents and the rest of their families.
Despite the secrecy and the Friar's good intentions, their marriage eventually leads to a series of tragic events and the eventual deaths of both Romeo and Juliet. The play is a classic tale of love, passion, and the consequences of hatred and family feuds.