I thought about the 10 22 but she really likes the AR 15 platform so I was thinking maybe a AR15 style 22
I agree with this statement above. Mossberg .22LR 715t are garbage & S&W much better. I also have a GSG .22LR "AR" style which is super picky on ammo and would probably just frustrate her due jamming. Or you could get a combo gun. The Savage M42 is a .22LR / .410 shotgun combo which sells for around $400.If you go with an ar platform for the 22 stay away from the mossberg 715t. They are garbage, at least the one i had was. Go with a S&W if you go with the 22 in ar platform