My 2- and 4-year olds both know what guns are and what they can do, but do not shoot yet (besides the nerf variety, that is). My 9 year old already handles my .357, AR-15, and 9mm with no problems. The 12, 20, and .410 are a little much for him right now, but he's small for his age. The only problem I have with him is he is actually really good, and he knows it. When shooting BB guns at Cub Scout events, he has a tendency to switch to left-handed (he is naturally right-handed) and other things just to show off to the other Cubs. I'm working on teaching him some humility, but at that age they know everything, and there is nothing else you can teach them.