I think those 8 gears will be plenty because I never use the front 3 gears, keep it in the middle one. So I only use 7 gears and that range is plenty for me even on hilly rides.

Cool that you guys are biking together, my wife and I just started riding together almost everyday. I just ride at her pace because I am in better shape. She is kind of weak because of lack of exercise, but once she gets her cardio back up and strenthens her leg muscles, I'm sure she will have no trouble keeping up with me.