The Catcher in the Rye presents a clear distinction between the world of children and that of adults. Children are genuine, caring, and kindhearted, whereas adults are "phony," self-centered, and generally "bastards." Because the story of told from the point-of-view of a disillusioned seventeen-year-old, we of course have to challenge the bias inherent in this perspective. The novel examines the grey area between these two worlds – namely adolescence – and the painful process of transitioning from one to the other.
Holden's narrative style and his unreliability makes it impossible for us to judge him as either a child or an adult.
What Holden thinks he likes about youth is just his idealized notion of what children are like. He's not in love with childhood; he's in love with a fantasy.