Have her check out the Cornered Cat website (google it). Lots of good info for women there. Then, drive up to Bass Pro and handle as many guns as y'all can. You'll figure out pretty quick what feels good vs. what doesn't. Take that list and then go find a place that rents guns and try a couple - different autos and revolvers.
Lots of choices, but some seem to rise to the top pretty fast -
Semi autos: M&Ps have changable backstraps; gives a near custom fit for all hand sizes. Springfield XDs, Glocks, and Ruger SR9s are all high-quality, large-frame autos. The glock and XD line also comes in smaller frames. The SR9 is already pretty thin. Smaller frame guns include Kahr, Taurus 709 (the "Slim") the Ruger LCP and Kel-tec. Smaller frames usually mean more perceived recoil.
Revolvers: Smith & wesson K-frames may be a bit big (model 10, 15, 64, etc.) but make good shooters. J-frames are easier to carry, but harder for rookies to shoot well. Ruger's SP101 is between the K and J frame, has enough mass to absorb recoil, and the grips fit most hands well. The LCR is a nice carry gun, but some find its light weight under recoil to be very punishing.
Have fun...shop around...and watch for a great deal.
Q