Before starting any kind of program, it's important to get proper instruction by an in-person professional, not just a video or through exercise demos. It's easy to injure yourself if you don't use proper technique.
Here's an article you might also find helpful:www.sparkpeople.com/resource/fitness_artic
"You may have a fresh start any moment you choose, for this thing that we call "failure" is not the falling down but the staying down." Mary Pickford