I’ll go first, I took my mom’s college textbooks which came with discs for a couple distros and failed to install RHEL before managing to get Fedora Core 4 working. The first desktop environment I used was KDE and despite trying out a few others over the years I always come back to plasma. Due to being like 12, I wanted to run my games on it, and man wine was not nearly as easy to use (or as good) as it is nowadays. So I switched back to windows until around 2015 or so when I spent the next few years trying to replace windows as much as I could. Once valve released proton, I switched fully and have t looked back, unless my still there windows partition tries to take over my computer when I restart it at least.
It was Ubuntu 8.04 in around 2013. I only did it to get a promotional item for Team Fortress 2 called Tux, a cosmetic item that looks like… Tux. I remember hating the UI/UX and promptly uninstalled it afterwards.
Eventually circled back around to Xubuntu for my low-end hardware and various other distros. Currently daily driving Fedora.