Fairies and the Quest for Never Land by Gail Carson Levine
Gwendolyn is a descendant from Wendy, who visited Never Land with Peter Pan. Peter gave Wendy a "kiss necklace," an acorn button on a chain. That necklace has been passed down through the family and now it is Gwendolyn's. The necklace sometimes show Gwendolyn visions of fairies from Never Land and she desires to go see them.
One night, Peter comes to take Gwendolyn to Never Land. When she gets there, she goes to Fairy Haven to see the Never Fairies. Mother Dove thinks that Gwendolyn might be a problem and almost sends her away, but Gwendolyn stays. When the evil dragon, Kyto, escapes from his prison, Gwendolyn might be the fairies only hope of staying alive.