You'd be surprised how many people go to uni for this shit, finish, and can not do what you are doing now.

I takes a certain kind of thinking to start from scratch and build a program. Most people could not do it.

Additionally, it takes focus.
People who struggle to focus on single problems, or to sit down to think, can't do it either. I think this is the main ability: sit down to code for a long time.

Thinking you are behind the curve because you don't know some algorithms and theory... In times of AI? You'd catch up within 1 year.

That all being said, programming as a career is ass.