I have the Glock G19 and LOVE it! I'm fairly wimpy, but have found the G19 is just perfect.
And like your wife, I don't dig the bigger calibers, which is why I like the 9mm.
btw-so far as recoil goes, I had a problem with recoil and my wrists sort of flipping back a little after each shot. HOWEVER, once I took a lesson and learned how to properly hold my pistol, it was no longer a problem. So in addition to the right gun, get her some good instruction!
And overall, what I've found, it takes time to get comfortable with shooting.