If you have a chance to try a class, DO IT! It is so much fun...even if you are overweight...even if you have 2 left feet...even if you hate working out with other people. Everyone is too worried about what they are doing to notice you, and it is a fabulous workout!!!
There are different levels of classes you can try if you are worried about high impact aerobic activity. I've tried tapes at home and didn't like it, but working out with an instructor is a blast!