When I was 15 or 16 I started in school with an Arduino and some sensors where my group was tasked to build a "self driving car" that could avoid obstacles. After we were finished with that I did a project based on this car on my own because I really liked the software part and this type of analytical thinking.

A couple of months later I got a programming book for christmas "C++ for dummies". This was the turning point. I learned how computers work on a pretty low level for a beginner which was not very motivating at times but there was no going back from this point on.

I think another important turning point was when I learned Git. It was the first time that I encountered code from different sources and opened my eyes to the idea of open source which was which was pretty intense.