I don't know what to do...

I think you should sign up for the dance class. The first class is usually the most fun because it's just warm ups and fun choreography to see your technique. You’ll blow them away then next classes. And you won’t miss enough to get behind. As a dancer you know choreography is easy to pick up on – you just have to use a break to practice.

 

Hmm.

If there's a way to talk to the teacher beforehand and find a way to makeup, do it

if not
Go to the first class. You know you can find a hundred other productive ways to protest, but can you make up a missed class that easily?