In William Shakespeare's play "Romeo and Juliet," Juliet begins to act more adult and mature in a number of ways. One specific example of this is when she defies her father's wishes and decides to marry Romeo, despite the fact that the two families are enemies. This decision shows a level of independence and mature decision-making that demonstrates Juliet's growth and development as a young woman. Additionally, Juliet shows her maturity by taking control of her own life and making difficult choices, such as choosing to fake her own death in order to be with Romeo. Throughout the play, Juliet demonstrates her ability to think and act in a more adult and mature way, despite the challenges and obstacles she faces.