First off, welcome to the forum.
There are debates all over the place, but I personally feel that a 9mm hollowpoint is plenty of stopping power if u know how to shoot (and 9mm is cheaper to practice with than the other calibers). Have you gone to the shops to hold any guns? That's what the decision will be based on...feel and how it shoots (if you can rent at your local ranges...where in IL are you at?).
How big/strong you are has little to do with how you handle the recoil of a firearm. Your experience/maturity as a shooter will determine how you handle recoil.
My girlfriend is a small-framed woman but she happened to like the bigger framed guns for some reason (she picked out the Stoeger Cougar so I bought it for her).
Once you go to a shop and handle as many as you can, then narrow it down and it will help us help you. There are too many options to help you out without you narrowing it down a bit. If you are trying to find a single handgun for the both of you to shoot then it might be a little bit harder, but you won't know until you go to a shop/range and handle as many as you can (and shoot them if possible).