I like mossbergs for a youth model. I am small so that is usually what I end up with is a youth model. They offer not only a shorter length of pull, but also the pump is closer to the reciever. I believe it has shorter rails on it to acheive this. And it can be swapped with the full size one, as well as a longer stock if you want to.

They also have a ported barrel to reduce recoil and muzzle flip. I didn't notice it did much for the recoil, but it helped quite a bit with the muzzle flip. I'm not sure if the 20's have the ported barrels, but I know the 12's do. I also think that is the only 12 gauge youth model on the market. I could be wrong on that though. I know when I was looking it was the only one I saw. The rest were 20 gauges, not that a 20 won't serve you well.

The mossbergs also come with three screw in chokes vrs one. You get an IC, modified and a full. And you can buy anything else you want. I had an extend modified and a turkey choke for mine.

You can also get other barrel combos for it. Like a fully rifled slug barrel or 50 cal muzzle loader barrel (she could deer hunt with either pretty well).

I think my mossberg youth model was like $254 out the door at a local gun store a few years ago. I traded it in on another gun recently and they gave me a little over 100 bucks on trade in.

If your on a budget I think the H&R/NEF's are great little guns. That was my first gun when I was kid. An H&R 20 gauge. They are very affordable and the single shot break action is very safe to train a youngster on. There a bit light though and tend to kick pretty hard. And they have fixed chokes, but you can get different barrels pretty cheap. And you can add weight to the stock. They come with pretty good recoil pads too.

If you can afford it an auto would probably be better on recoil because of the action. I don't know much about those though other than they are sort of pricey. I will let someone else handle that.

Another option would be to get her a H&R handi rifle in .243 or something and get a 20 guage bird barrel to go with it. That would be an excellent combo. I believe Rossi actually sells them paired together, but I don't have any experience with Rossi's. The onese I have looked at seemed like cheaper versions of the H&Rs.

Good luck,
Paul