J.D.
I'd probably not fight it to much. It's allowing her to find who she is. She'll get bored with it and move on. I would however offer up a lot of variety and try to find other things she likes. Strawberry shortcake? Carebears? American Girl Dolls, etc. If it makes you feel better...my son is 3.5 and he is OBSESSED with this pair of woody boots that my mom gave him. Woody light up cowboy boots. He practically sleeps with them on. His famous outfits are pjs and woody boots. I made a rule..no boots outside aka IN PUBLIC! LOL. My reasoning...no outside shoes inside so if he wants to wear woody boots in side he can't ware them outside. It works. He is also obsessed with CARS the movie. But I've noticed some times there are periods where he totally doesn't think about it and then others when its all he is interested in. I know boys are different than girls...