It was the early 2000ās.
I got sick of the constant bluescreens in windows at the time, so I decided to try something different.
Itās gone in fits and starts over the years, but at this point I have been using Linux as my primary OS since ~2001 or so.
I still dual boot to Windows for games.
(Linux is getting better at gaming all the time, but it still does not provide the performance I demand in games, in part because AMD GPUās are the only ones that really perform well in games under Linux, and there is no AMD GPU that is fast enough for my 4k Ultra quality demands)
I also still use a Windows VM for my work stuff (because I need to use the Microsoft 365 ecosystem that pretty much every professional setting uses these days).
Other than that, I am 100% Linux, and have been for almost 25 years now.
My first Linux experience was actually in like 1994 or something, when a PC magazine I bought came with a CD Rom that had some old version of Slackware on it. I tried it, didnāt like it, and switched back to DOS 
Then in 2001 I briefly experimented a little with Linux for my game servers (I ran some high profile community Counter-Strike servers from ~2001 until ~2005). For those I used old pre-RHEL/Fedora split, RedHat.
Then a couple of months later is when I had had it with Windows and blue screens and decided to install Linux on my desktop.
I started with Gentoo Linux, because I liked the idea of optimizing C-Flags specifically for my hardware. Back then, Gentoo didnāt ahve an automatic installer. You had to boot up a live image, and then bootstrap your system compiling all of th epackages to be installed. This took a long time on 2001 hardware 
The practical benefits of that were probably limited, but it appealed to me at the time.
Over time I struggled with Gentoo often breaking. I had to run the unstable repositories as I am (or at least was) a ābleeding edge hardwareā kind of guy, and often nothing but the unstable branch would work with my hardware.
At some point (I want to say it was ~2006) I just got tired of things breaking all the time and having to spend hours troubleshooting to get my sound back, or something like that, so I decided to try alternatives.
I switched to Ubuntu. (I think it was called āUbuntu Linuxā at the time, but that seems to have been erased from history in favor of just āUbuntuā After being used to Gentoo, I was astonished at how everything (or at least almost everything) in Ubuntu ājust workedā. No workarounds to get shit working. No hunting for rare kernel driver modules. I just installed it, and everything worked. I liked that.
Then in 2011 Ubuntu decided to use the Unity interface as the default desktop instead of Gnome2. I absolutely hated it. I know I could have just installed another desktop, but I took this as an opportunity to see what else was out there. I landed on Linux Mint. First their Gnome 2 version, but as Gnome 2 was abandoned and no longer maintained, that split into the Mate branch (a Forked version of Gnome2 for purists) and the Cinnamon branch (a from scratch Gnome2 work-a-like, but more modern).
I tested both, wound up liking Cinnamon more, and have been using it ever since.
Over time Mint has become more and more amateurish though, trying to ship a desktop with a lineup of packages all pre-installed, where everything is configured from the GUI, etc. etc. Having been used to command line configuration since my Gentoo days, I really chafe at this.
Mints dependence on Ubuntu is also really starting to annoy me, as over the years Ubuntu has had no shortage of controversial episodes where they try to bully and take over the Linux world.
I am considering another switch, but havenāt really gotten around to it yet.
I really like the apt package manager (and hate blob distribution like with Snaps, Flatpak or AppImage with a passion) This limits me a little bit.
I might just go with vanilla Debian at some point, and manually install the Cinnamon Desktop on top of it.
Debianās package base is often a little older, and that can cause some issues, but that also means it is tried and true, and I like that.
Iām still undecided. Time will tell.