Hey nic long time no see. So you want to get her a gun hmm good idea much better than a ring. If you have no idea of what she needs then just buy what ever gun you are planing on and after you give it to her start cutting the stock down. Start by taking off the recoil pad then have her shoulder that. If it is still to long then just go by 1/4" at a time when she says good measure the thickness of the recoil pad cut that much more off, put a pad on and you got it. Depending on how much you take off you may have to get a new recoil pad that is shorter or modify the original since the height of the butt will decrease as you cut more off. It would be a good idea to get one that has an adjustable drop and cast by way of shimms but that is a luxury that makes life easier.