How do I talk to my mom about this? :)?

I weigh 169 Pounds, I'm 5'1, and am 14 years old. I saw this add on television for Tracy Anderson method, and I really think I should do it. My problem is talking to my mom about it. I don't want my family to know that I am doing this program, I don't want to think I am insecure about my body (which I am), or they will treat me differently. I want to be healthier and be able to do the things my friends do. I feel awkward talking to my mom about this, how should I , you know.....bring it up :) It be nice if you could be help me out, thanks :)