When you take her shotgun shopping, remember that shotguns are laid out with the average American male in mind. If she's not on the tall side for a woman (5"9" or taller) that shotgun's stock is going to be too long for her. That's going to stretch her arm out and screw up her ability to form the pocket that the butt needs to sit in when the gun's shouldered. Shooting a shotgun that's too long in Length of Pull is like trying to run a marathon in shoes a couple sizes too big. It can be done but it's going to be painful and far from enjoyable. If you get the stock cut to fit her (length of pull, cant, ..), she should be able to handle a 12 gauge easily.
If the recoil is still a bit much for her, along with tailoring the load selected, look into a recoil reducer like a Dead Mule and a good recoil pad. They make 2 kinds of Dead Mules, one goes in the magazine and the other goes in the butt stock. Since this gun's intended for HD, I'd drill the hole and mount it in the butt if you end up having to go this route and get a good recoil pad fitted at the same time. I've seen women that were 5 foot nothing and weighed a buck and change run the crap out of a pump 12 gauge after the gun was set up to fit them.
If you end up having to shoot the gun, having it set up for her is less of an issue. Shooting a gun that's a little too short is much easier than shooting one that's too long.