As a group fitness instructor, how many different workouts should I have in my repertoire for each type of class I teach?

My first classes went well thanks in no small part to all of your helpful advice. I did have to modify several exercises and shorten the cardio portion based on fitness levels of my participants. They were all good sports and very kind to cut me some slack as a beginning instructor. I think we will all be a little more relaxed next week and better able to enjoy the class. I am going to LOVE my new career!