started at 7 also, at age 12 was allowed to hunt and terget shoot unsupervised, never had a problem.
When my daughter was 4, I showed her the shotgun in my closet, I explained the dangers of the firearm to her, and expressed to her that she is to never touch the gun, whenever she would come into my room she would always ask me to show it to her, and when I would, the first thing out of her mouth was I dont touch this gun daddy, i only look at it with you.
So teach the children about the guns, and that will keep the curiosity of finding this thing that they know nothing about from overpowering them and resulting in them playing with it.