You are in a beginning class, aren't you? If that school has placed you according to age rather than experience you need to find a better ballet school. There is no way you can catch up with students who have had even one year more than you, and you would find yourself condemned to biting your elbows in frustration and being the worst in class. That just normal, and it is not your fault. Now there is the possibility that this was an audition class-- so the teacher could see you and place you in an appropriate class-- this is what most of the better recreational schools do. If that was the case you should have been told. Wait and see what happens in the next class, see if the teacher puts you elsewhere. If not, tell her you need a BEGINNING class, and if she doesn't have one with students approximately your age, find a better school. Don't let this experience sour your desire to learn to dance.