I don’t remember how old I was when Dad took my brother and I down the basement and set us up with a BB gun and a target box. Certainly I was less than 8 years old. Dad was a combat veteran of both the Marines and Regular Army (separate enlistments, different wars) with rifle marksmanship awards from both. He taught us the basics of safety, handling, and target shooting.
I’ve forgotten a lot of stuff in my life, but not one word of his training has escaped me to this day.
PS: I also became somewhat proficient at close order drill long before I joined the Boy Scouts.