One reason why I think Holden acts childish is because he wont talk to his parents because he failed out of school. Hes running away from his problems and wont take responsibility for what he did. I also think its funny when hes at the bar and hes dancing with the woman and he tries to act older by swearing alot but the woman doesnt like it at all and thinks that he is very immature becuse of it.

I think Holden tries to be more mature when he leaves the school and is on his own for a little while. I think he wants to be more of an adult than he is actually ready to be.