I agree with a couple of others, particularly about individual progress at a young age.
99.9% of all children taking dance classes are not 'cut out for it' in one way or another. They don't have to be. Cut out for what, anyway? The whole point of recreational dance is that it is supposed to be a fun, enjoyable activity, just like most other things. And that is what you're paying for. You are not paying for on-the-job training.
There will always be a select few who appear to be the teacher's favourites, or always get picked for main parts or take their exams early. They aren't favourites - they have greater potential or inborn natural talent. That's just the way it is. It does grate with parents, because you are all paying good money for classes, and expect your child to be treated equally. Life's not like that though.
OP, as another pp mentioned, it is far more usual for dance schools to have a watching week at the end of every term, so you can see your offspring dance, and you can see what your money is paying for. The teachers should also be happy to talk about your dc and you shouldn't be getting brushed off. You are a paying customer, and if you aren't entirely happy with what you are getting, then please consider whether she (and you) would prefer a different dance school.