That's great that you're working out! As for the foot numbness, is it just the toes or the entire foot/feet? Sometimes I have that when I use the elliptical machine, and I think it might be connected to tying the laces too tightly on my shoes or wearing socks that are too thick.
I can understand being really motivated when first beginning to work out, but I've been a member of our gym for about 6 years and have seen lots of newbies come and go after a couple of months because either they're burned out from pushing too much too soon or because they don't have a workout partner to keep them going. I myself have injured tendons from pushing myself too much when doing a new workout. Just be careful, stretch out beforehand really well, and enjoy it when the endorphins kick in.
~Lisa