I switched probably 2010 or 2011. I think I was on windows 7, but it might have been windows vista and I never got to 7.

At some point I had made a realization that software I downloaded from sourceforge (this website has been terrible for a long while now, but I think it was decent way back) was heavily correlated with not being shitty. After making this observation, I was able to generalize it to open source software tends to be less shitty and I had a year or two of experiences afterwards that reinforced my theory, which led me to try experimenting with linux installs.

I started with dual-booting Fedora, I had no idea what I was doing and didn't like the user experience as much as windows at first. I did a little bit of distro-hopping to see if there was something more appealing to me, but during that time I discovered the free software movement and that resonated with me a lot more than open source had, so I decided I wasn't interested in going back to windows. Moved to Trisquel (originally an Ubuntu derivative, and fully-free to the point of being FSF-approved) and grew to love it.

After a couple years, I decided I was curious enough to learn more about how the system works, so I moved to Parabola (fully free Arch derivative) to force myself to learn. I really learned barely anything, but I got very good at getting things working by trial-and-error while reading documentation I don't fully understand. I haven't progressed very far beyond that point at all in the years since, but I got too comfortable to make a significant change.

In the past five or so years, I've to some degree dropped the free software philosophy in favor of a philosophy that the problem runs much deeper (no hope of a successful free software movement in a capitalist society, and software is not even close to the most beneficial consequence of getting past capitalism), and I've moved to legit Arch rather than Parabola.

I've basically gone ten years without real issues on arch installs, but I still have no idea what I'm doing, I'm just comfortable with it and don't want to put any effort into a change. I feel like if anyone from the arch forums or anyone knowledgeable in general took five minutes to look at my pc they'd be like wtf are you doing. It's whatever, it works well enough for me.