It is clear that this text presents childhood as some sort of idyllic time where the innocence of children has yet to be tainted by growing up. The tale centres around a boy who does everything he can to not grow up and to stay in his childlike state forever, after all. Peter Pan refuses to play "father" to Wendy's "mother," as this is obviously too uncomfortable to him, and when he has the opportunity to be adopted by the Darlings, he refuses, as this would mean he would have to leave his territory and grow up some day. However, it could be argued that such an effort is actually wrong, as all children must grow up and this is part of life. Note how the theme of childhood is introduced quite early on in the text:
All children, except one, grow up. They soon know that they will grow up, and the way Wendy knew was this. One day when she was two years old she was playing in a garden, and she plucked another flower and ran with it to her mother. I suppose she must have looked rather delightful, for Mrs Darling put her hand to her heart and cried, ‘Oh, why can’t you remain like this for ever!’ This was all that passed between them on the subject, but henceforth Wendy knew that she must grow up. You always know after you are two. Two is the beginning of the end.
In spite of the slight exaggeration in the last sentence, the message is clear. No matter how much it is wished that childhood is a stage that is permanent, the fact is that children must grow up, and there is a slight ambiguity in the text about Peter's insistence that he will never grow up that indicates this may not be entirely healthy. Childhood is therefore presented as a magical time, a time of innocence and imagination where anything is possible, but ultimately as a time that must pass and, unless your name is Peter Pan, is not forever.