Susan,
I do both programs as Margaret said and enjoy them. But, I would not recommend that you start both at the same time. I think that would be really hard and suggest that you start with only one and stay with it until you feel ready to move to the other. It really doesn't matter which one as that are both really good. If you do have any health problems, then Qigong might be the one to do first. After you are comfortable with one, then you might want to begin the other.