As a student at The Bronx High School of Science in the early 90's, I discovered we had access to this thing called the "Internet".
Access was through various terminals throughout the school, mostly IBM X Stations. Our servers themselves ran IBM's AIX and so through this I discovered this new, challenging operating system called UNIX. (yet familiar, as at the time, MS-DOS was the dominant PC OS).
Soon after I learned of Slackware from a fellow computer geek. I started using GNU/Linux as was hooked. Have used it in one form or another (with the exception of a brief hiatus to try FreeBSD) ever since... now over 20 years!