It really doesnt matter what gun you get her as long as she goes to the range and learns how to use it proficiently and regularly, that is the key. You could get her a .50 cal rifle and yea at first its going to rock everyone's world but the more you use it the less scary it becomes.
Example: when I first got on my SO's SWAT team the pressure from the muzzle blast of the M4s we shoot was very distracting when 6 guys are shooting one target in a 10x10 room. Now after repeatedly clearing and shooting in confined spaces, it is second nature for me to get my partners muzzle blast in my ear and keep looking for someone to rescue or kill without skipping a beat.
PM me if you need anything.
Example: when I first got on my SO's SWAT team the pressure from the muzzle blast of the M4s we shoot was very distracting when 6 guys are shooting one target in a 10x10 room. Now after repeatedly clearing and shooting in confined spaces, it is second nature for me to get my partners muzzle blast in my ear and keep looking for someone to rescue or kill without skipping a beat.
PM me if you need anything.

. Good luck. Keep us posted.