I don't have kids so I can just tell you how I learned about guns as a kid. I was 8 years old, was handed a Crossman BB Rifle, 1000 or so BB's and some paper targets. I was told to go out in the back yard and shoot away.
I was unsupervised and unskilled in the use of any firearm. I learned sight alignment, trigger control and some safety by myself. I also did some stupid stuff with my BB gun when my parents were not home.
I shot out a few windows, shot a few cars... a police car once. Ironically, the officer was pulling into my driveway for my earlier shooting out of a window. I got in some big trouble.
Moral of this story, teach your kids/grandkids about guns early. First time I fired a "real" gun was when I was 21 years old. I was scared to death and was shaking very nervously. Don't let that be your child/grandchild.