I think I'm more jittery over the BOOM a muzzleloader makes than the actual recoil. I'm more leery of my short barreled White Mountain Carbine than my encore, simply because stuff is happening closer to your face, and it's louder. Just something to think about if a carbine is in consideration for this young lady.
I like Cayugad's suggestion of the buffalo ballet. Shockwaves don't do well (lack of expansion) with lighter powder charges.