Definitely a tragedy, but brought on by lack of training of the child by the instructor. She should have, after firing single shots, had a magazine with perhaps three rounds in it, so she could learn the recoil.
I was taught gun safety and marksmanship when I was 6, by my father.
I take my 7 year old grandson shooting often. He uses an Smith and Wesson M&P 15-22. This is a .22 caliber rifle that looks like an AR-15. It is of course semi-automatic rather than selective fire. I'd trust him to use a selective fire weapon AFTER proper training as I described above.
There is nothing wrong with teaching children about firearms, in fact it reduces the "Johnny shot his sister" accidents you hear about. If they know what a firearm is all about and know the 4 rules they're less likely to have an accidental discharge ending in tragedy.
1. All guns are always loaded.
2. Never let the muzzle cover anything you are not willing to destroy.
3. Keep your finger off the trigger until your sights are on the target.
4. Be sure of your target and what is beyond it.