I first heard of it in the early 2000s, with my dad talking about replacing our buggy Windows ME with Lindows. Eventually, that computer died without us ever attempting to install it.
In college, I hung out with someone who used linux and thought it looked cool. I successfully dual booted Ubuntu on my PC around 2005 or 2006, but could never get the video drivers working properly (it was stuck at the lowest resolution) and eventually gave up on it.
I started adminning a web forum around 2014 or so, and the previous admin talked me into dual booting Fedora rather than only using Putty. So I started using it intermittently whenever I started working on the forum, though I never really got into GNOME. He also told me about raspberry pis, so I picked up a pi 2 and started tinkering with it.
When my wife moved in (2018), she (a software developer) was working on a project and asked me if I’d heard of raspberry pis, as she was recommended to use one but hadn’t looked into it yet. I pulled my pi 2 out of storage and she fell in love with it, so we started buying loads of pi 3s and zeroes, with me testing out different distros and setups for her while she was working on the project code.
Finally, somewhere around 2018 or 2019 my laptop started running like shit on Windows. I tried out Xubuntu and fell in love with it. It ended up becoming our go-to distro, getting slapped on old desktops she brought home from work and a used laptop I bought for our daughter. So that became the daily driver on my laptop, even as she moved onto Alpine with i3wm.
And now we both have Pinetab 2s, so I think it’s fair to say we’re full on linux nerds at this point. We still have Windows on some of our desktops, though, so we’re more pragmatists than linux proselytizers.
TL;DR: I heard about it young, and that interest grew into dabbling, until I finally got addicted to it.