I go as often as the Y has classes. I love it! You should try it! I was so afraid the first time because I can't dance and am so out of shape. I had no idea what I was doing. I stayed in the back of the class, but it was fine. Everyone pretty much worries about themselves, and if you stop for a second and watch, everyone there looks as crazy as you feel! I find myself at home the next day dancing around my house to the zumba moves.
Are you wearing sneakers at home when you do it or? There is so much jumping/bouncing, I can't imagine doing it without, but then again, you will be inside your house.