My boy started off quite young and he was recoil sensitive. I went with a Model 7 youth in .243 Win and made light loads for him using 85gr Nosler Partitions. I never chronographed the load but I doubt it would have been more than 2700fps - probably quite a bit less. I believe the load was 33gr of IMR 4064. There was virtually zero recoil and the load is surprisingly effective. I also tried a full sized 7mm-08 using 120gr Nosler Ballistic Tips and that was too much for him until he was about 13 or so. All of the sudden he is fine with it, fine with moderate .270 loads and even fine with moderate 7mm RM loads out of a heavier rifle. I make sure he shoots prone, sitting and with a bog-pod as well. He found it quite challenging the first time he moved away from the comfort of the bench.
I would suggest a T3X Compact and load 85-100gr bullets to around 2700 fps. You can use regular cup and core like Hornady SP for practice and the little Partitions for hunting. That will save some $ in the long run. The Weatherby Youth models are nice too, but kind of heavy. Make sure the rifle futs her and a good trigger is, IMO, important.
Don't worry about the lower velocity - a properly placed broadside shot on deer at 150 yards or less will end up with a happy little huntress.
