I rebuilt my first lawn mower engine when I was five, so I suppose it had to be my Dad who taught me this stuff at an age so early I cannot remember.
Dad taught me all sorts of useful things, including how to ride a bicycle, treehouse engineering, etc. but the one thing he didn't care about and we didn't cover was sportsball. I think that worked out for the best anyway.
Dad taught my sister and I to read when we were four (my sister is two years younger than me, so she got even more of a head start on her letters by watching my lessons). We arrived at kindergarten (five years old in the US) reading comfortably at nearly a sixth grade level. Turns out, this REALLY gums up the works in schools. They're simply not equipped for such a thing as a wee tot who can actually read.
I was bored to literal tears, and got in trouble many times. I was forced to do many worksheets and exercises over because I got them done too quickly and accurately, and had to be "cheating" somehow.
Finally, I was "caught" and punished for sneaking in Popular Mechanics to hide in our basic letter books. The teacher was absolutely convinced that I was "pretending" to read and not paying attention to learning the basic letters. I asked her to bring me any book or magazine to show her I could read, but she refused to perform the experiment.
I didn't know the word "apocalyptic" yet, but let's just say Mom brought both the thunder and the lightning to the principal and teacher the next day, and they drank deep of fear... I was called in, handed a random magazine, and told to read a random paragraph aloud. After several repetitions, the teacher and principal had to agree that I could, indeed, read.
Some sort of compromise was reached where I could read more "advanced" stuff, as long as I could explain what I had read. And for some reason, I still had to do all the same worksheets and exercises as my classmates. Articles in Popular Mechanics and Popular Science soon surpassed the teacher's ability and interest, and I was mostly left alone for the rest of kindergarten.
Rinse and repeat for the next several years... I really feel sorry for kids who were a little different in any way and didn't have a grizzly bear for a Mom.