I had my first .22 at ten years of age. Dad made sure there was no ammo in the house, we made a trip to the store on plinking day and shot it all up to the last round.
I knew where my Dad's pistol was kept by the age of five. He moved it around for years, he knew I knew, and I knew he knew I knew the secret. I found it every time within a day or two. I knew better than to play with it, but the point is, I knew where it was, went to it often enough, and luckily knew better than to play with it.
Dad sold the pistol around my 13th birthday. Years later he said, "I knew the difference between a young boy and a teenager. Teenagers cannot be trusted, no matter how good they were a couple of years earlier. No creature on earth is dumber than a teenager."
Better safe than sorry.