I agree with the others, get something like a Remington 870, in either 12, 16, or 20 gauge, and tailor the loads to her. There are also recoil reducing stocks available, such as this one that you could consider. I have never shot a weapon equipped with one, but have talked to others who have, and they love them. You might also get a short (18-20") barrel for it, much easier to maneuver in a building...