My 12yo granddaughter fires my .50s with no problem at all, using round ball (~180 some-odd grains.) She doesn't like the 350grain and up projectiles, yet, but is working up to them. This is from the bench or prone. Shooting offhand, I haven't found a load she can't shoot and enjoy.
I don't feel the recoil is a factor at all, compared to my other big-bore rifles (30-06 and 8MM Mauser.) Until I load up to above 300 grains of bullet weight and 100 grains of powder, I don't notice recoil at all. Then again, I make sure my guns FIT me and I use proper form in holding the gun to my shoulder.
Armed and Safe: Not just a theory
If it time to bury them, it is time to dig them up.
Remember, "Behind every blade of grass."