You probably want it to be a surprise, but if possible let her handle, dry-fire, and shoot the options. My wife doesn't care for revolvers (where I was thinking she would go), she liked the small size of the Shield but didn't shoot it nearly as well as a Glock. So she ended up with a Glock which she thinks is perfect. She liked the G20, G22, and G23 and hated the G27 size.
As mentioned, technique does make a huge difference in racking the slide.
