Holden's interactions with his little sister Phoebe show his maturity. He acts as a role model to her, or at the least attempts to in her presence. She is the only person in front of which he feels guilty about his negative actions, such as getting expelled yet again from yet another school. He is also mature in the way he understands the vast differences between childhood and adulthood, though his reaction to adulthood is to come up with plans to run away and avoid growing up altogether. However, he realizes what is about to happen in his life now that he is growng up.