Donna went from the "childhood requirement" Daisy Red Ryder bbgun to a Ruger .22 automatic pistol, then a .38 small revolver, then to using .38 Special bullets in a long barrel 357 revolver. Now she uses .357 Magnum rounds in the 357 and thinks she's something. :-)
I bypassed the .22 rifle stage with her, as I had mine stolen and never got around to getting another one. I think she'd enjoy it - but knowing her, it wouldn't be once or twice out with it when she'd be asking for a double barrel shotgun. That girl just loves the kick, I guess!
I'm not sure of the "age" she was at each stage, but I do recall what I used to determine when she got the .22. I kept repeating she could have the gun when:
"You do WHAT you are told, WHEN you are told, CONSITANTLY, WITHOUT SUPERVISION."
She would say it right along with me and in time she figured out I wasn't giving in until she met that requirement, regardless of age!
One consideration for a smaller kid, though - I know I gave away the .22 automatic because I don't have a smooth enough finger pull through, and kept jamming the gun because of it. If a kid is not able to smoothly pull the trigger, either, the revolvers are the way to go. There is no use in a gun that you can't fire reliably, and they are very forgiving on the trigger pull. I haven't had a revolver jam, yet.
Don, you are always welcome to take the .38 for a while, if you want to introduce him to handguns.