How to ask my mom for a workout DVD? It's just an awkward convo?

I'm 14 but I really hate excersising. I know I need too so I thought that a workout DVD would be a good idea. I want to try a Tracy Anderson DVD, because I heard she is really great. I just think it would be really awkward to ask because I weight like 120 and I'm 5'7.5". Should I just save up for it myself?