aren't all little girls supposed to be shaped like eggs?

I had a wee bit of a dilemma over the weekend. A body-image dilemma, concerning Rosie. There are sooooo many poor models out there for what a "normal" body shape is that I just won't bother to list them (cafgh-Barbie). I somehow didn't expect them to be reflected in a four-to-five year old's ballet class, though (@ 12, maybe).

Don't girls only start to have defined waists when puberty starts its work? Apparently ballet costume sizing charts have a blind spot to this.

At the end of Rosie's Saturday class, I received said form and dutifully, took her measurements at home. Here's how her sizing worked out: chest, small; hips, small; girth (shoulder to crotch): small; waist, LARGE? Whaaa?

I read through, and the proportions are the same for adults and kids, narrower in the center. Grrrr. Stupid!

Now I have questions. What size do I actually order, and should I start doing situps with Rosie or yell at her teacher for dealing with such unenlightened costume manufacturers?