Lass - I love ballet. Adore it. Did it seriously (White Lodge etc) for a long time. Nearly went pro but realised I wouldn't be good enough to be the best. Still try to do it now, though my hips and toes (see above) are increasingly protesting.
I have taken DD to lessons. I go as often as I can to watch performances at all levels (local ballet schools as well as professional companies).
That doesn't change the fact that ballet can be problematic for feminism, particularly in relation to young girls. I bet those sell out audiences watching the Woolf production are not full of five year olds who try to copy the steps at home in their bedroom. Seven year olds don't doodle the plain tunics of most modern ballet, they draw themselves in classical sticky out tutus.
(Ballet can also be problematic for people of colour, but that's another thread)
The OP's original concern was about her very young child and the "princessification" stuff - legitimate concerns, it would appear, in relation to that particular ballet school. As pp have said, there are plenty of ballet schools that wouldn't let a yard of tulle through their doors, never mind encourage the pink and sparkley image. Ballet can be fantastic exercise and has many many positive attributes - not many hobbies are entirely without a downside.
I would always recommend that girls (and boys!) try ballet and see how they get on. I do so in full awareness of the issues that ballet can raise, not trying to sweep them away.
(But I have often said on here that I am a Bad Feminist)