My daughter had learned the four rules, and ten commandments of gun safety, by age 8. When she was 11, I took her down to the range/gun shop and let her pick out her very own pistol (.22), and as a special treat we rented a MP-40 machine gun. She was curious, and after about 10-12 rounds, didn't want to continue(curiosity sated). I was on her left side, the instructor/clerk was behind her, and we were both ready to take control of the weapon, in case she was not able to control it.
There's no such thing as an accidental shooting, only criminal negligence.