I remember when a gun instructor let a little 8 year old girl use an Uzi. It would've been fine of he let it stay on single fire mode or whatever it's called.
It would be even better if an 8 year old wasn't firing a firearm in the first place. It doesn't matter what mode it is on if that thing as kick to it the kid can still hurt themselves if they're not strong enough to handle the recoil. Even on semi the thing can kick up at them or whoever and they may pull the trigger.
there is nothing wrong with letting a child use a gun if they are being responsibly taught how to care and use it. the instructor made a mistake making it go on full auto mode and that cost him his life.
Except when the gun has high recoil to it.
it was semi automatic when she first started the lesson, the instructor put it to fully automatic after several practice shots with the kid.