I started my daughter out when she was 6 shooting a pump Remmy in 243, that I aquired second hand. I put up a full sized deer target and she went to it. Recoil never seemed to be much of a problem even with 100gr loads, as we only shot it around 6-8 times per outing. She was shooting 3-4" groups with it right off the bat.
As luck would have it, we didn't get her on a deer till she was 9, and when the time came she waived off the .243, and took down her first little buck at 180yds with one shot from my 25/06.
Since then, I have to fight her off it every season, so be careful of what you let him shoot or you might have to fight for it. [img]/ubbthreads/images/graemlins/grin.gif[/img]
She took this one at just over 250yds from a kneeling position across our back pasture. Then was upset as the "big one" she was after slipped off through the woods after the shot.
Good luck with your daughter, it is a total rush when the time comes for the first shot on game. I could hardly sit still wanting to help out, but at the same time trying to let her do it all.