I love thinking about this as I have two children I want to teach how to cook.
1. I recall "home ec" in eighth grade - learning the difference between liquid and dry measures.
2. I made cookies and bar cookies a lot in high school, very successfully; I also distinctly remember the time I rooted through my mother's spice cupboard and dumped all kinds of things on potatoes as I fried them. They tasted different and better.
3. I was a "salad bar attendant" at a local restaurant when I was 16, and that involved making broccoli salad and some other stuff I can't remember; I was learning how to chop, measure, and combine savory things, not just cookies.
4. I bought myself a More with Less when I was in my first apartment in college and cooked a bit with my housemate from the Virgin Islands; I remember my astonishment when she made yeast bread and dumped in water until it "felt right." I had never seen someone make bread, let alone by feel. From then on, I was deeply captivated by cooking and baking.
But I do not recall being instructed in the basics at home, although I'm certain my mother must have taught me because I learned how to make cookies somehow.
(Posts where I show my children learning in the kitchen: dumplings, chopping mushrooms, peeling eggs, and Christmas cookies.)
I'd love to hear how you learned to cook and how you plan to - or do - teach the youngsters in your life.