Ninth grade
Computers were the first thing I wanted to understand. I liked machines I could watch work, but electronics happen inside a box, and nobody could explain how. That drove me to figure it out. Thankfully, an opportunity presented itself in ninth grade. I traded my free periods, lunches, and homeroom to a school IT staffer who agreed to teach me in return. The principal okayed it as long as my grades held up.
Fixing computers is mostly a long stretch of not knowing the solution, followed by a rewarding aha moment. By the time I graduated, I had repaired hundreds of the school's machines, and that's where I got hooked on that moment of clarity.