well tell your mom of something else u might do or if that doesn't work you can always scare her and tell her that if you do dance u will have less time to focus on your studies and you"ll start falling! she will not want that and so she give up. i;ve been a dancer my hole life i like it but if you don't like it you will not be good so don't embarrass yourself. also dance is VARY clicky so if u haven't been going there for a while and your not vary good most of the group will not except you. try to explain this to your mom and maybe you'll change her mind.
hope it all works out
hope it all works out