I once sang an audition for Mary Lennox and I used "Happiness" from YAGMCB. (I got the idea from the version on the Broadway Kids CD, which is very head-voice light and sweet sounding, NOT the Broadway revival version.)
People might suggest "Castle on a Cloud," but I'd stay away from it because it's so overdone.
I believe there's a song from Gigi, "The Earth and Other Things," or something like that -- can't remember the exact title. It might be the right kind of piece you need.
Do you sing soprano? If you do, you could look at the Hansel and Gretel duet from the opera (!!!) by Humperdinck. The melody line is beautiful and sweet and young, but only if you are comfortable in a soprano range.
I'll post again if I think of any more.
Posted on Oct 21, 2008, 7:57 PM from IP address 22.214.171.124