Cheryl,
We have the Minnie dress also....bought it when Ayden was not quite 2 and it still fits. We also bought a Snow White costume at the parks....we were supposed to be getting Cinderella but couldn't find it anywhere in her size that week. Cinderella is her favorite.
I think I may just give in and buy the Cinderella dress if we can manage it....which means I have all the fabric, notions and pattern for a Cinderella dress laying around unused. Oh I get so mad at myself for doing that! But I'm so tired right now I'm barely managing my regular everyday stuff!