I guess I was about seven, maybe 8 when I got a BB gun for Christmas. No special instructions, neither of my parents did any shooting, but there was a "safety instruction" card with the gun.
I did manage to lose it twice. Once I thought it was unloaded and it wasn't. I shot it in the house. Lost it for a week that time. Then once I shot my sister with it. Didn't mean too. I had stuck a cigarette pack on top of a pile of cinder blocks for a target. How was I to know an empty cigarette pack wouldn't stop a BB? And I didn't know she was back there. She jumped up, rubbing a spot on her back and screamed "I'm going to tell!" Then she went into the house, turned on the tears, and bawled like a calf with it's head stuck in the fence. Sisters can do that. Lost it for a month that time. Learned a lesson both times. They're always loaded, and make sure of what's on the other side of your target. Haven't made those mistakes since.
Got my first "real" gun when I was 13 I guess. A 20 ga Ithaca Supersingle, single shot. Shot it for the first time standing on the back porch shooting at a can I tossed out in the yard (we lived WAY out in the country). I pulled that empty shell out, held it to my nose and breathed that smell that only a fired paper shotgun shell has.
I was hooked.