I've grown up around guns all my life. My family is a very "gun friendly" family. Growing up, we had guns in the house and I knew where all of them were (even at a very young age). I shot my first handgun at around 8-9 years old under my dad's close supervision. None of us kids ever shot each other or ourselves, nor did we have anyone come in and shoot any of the family.
My sister, when she was in college (about 20 yrs old), did however shoot someone who was breaking into her apartment. Saved the life of her and her roommate. The man breaking in was threatening to rape and kill them as he was trying to get into their place.
He got his hand into a vent window and was about to unlock a large window to climb in. This was in Oklahoma, and the law at the time stated you could only shoot whatever bodypart was in the house. She shot his hand and the bullet went through his hand, through the window, and into his shoulder. She did this with a .38 cal handgun (snubnose) at a range of about 12-15 feet (across the living room).
The man fled to the indian reservation and could not be arrested. My sister and her roommate moved to Washington state.