Personally, I was a left liberal for all my life, but had kinda looked into the abyss of anti-sjw and gamergate stuff, like watching Sargon and Bearing, but hadn't really subscribed to their beliefs, more putting them on as background chatter.
Things changed when I read manufacturing consent, listened to Chomsky and found Chapo at around the end of 2018, at which point I found myself as more an ancom, but Chomsky's talking points on Leninism and the USSR was never as cogent and didn't make as much sense as his other points, so I held skepticism about my beliefs then.
Reading more on theory and history, and looking more into different left tendencies via channels like Rev Left moved me over to be a Marxist, as it made the most sense to me in explaining the current and historical situation. Currently making my way through Lenin and looking more into historical ML states and I've found that I'm pretty comfortable as just a Marxist with ML tendencies rn.
Got into Punk music in High School. First election I was old enough to participate in was Bush v. Gore - and I fucking hated the Bush administration. Every so often, while listening to shit on the radio, I'd hear a clip from this obscure congressman from Vermont, who would lay into all the other politicians for all the right reasons. I really liked him, but was ignorant of any larger movement and otherwise kinda nodded along to much of the liberal ideology. Bush was the first president I was aware of as anything greater than a character on Animaniacs, I despised him, and the democrats seemed like the ones who stood in opposition.
The Obama administration was largely disappointing, but the liberals were convincing enough at the time at pushing this idea that their hands were tied by Republicans, and if only not for that, then it'd be smooth sailing. And that was when that congressman from Vermont, now a Senator, ran for president. The day he announced I was stoked, and was thinking this will be cool, maybe he can get like 5% support, and his ideals could get discussed a wee bit! But the campaign that began on a lawn, with little fanfare, quickly grew. As such, I soon discovered that I was far from alone. Equally important, I learned just how little the rest of the Democratic party seemed to like what he had to say. I think that's what brought me over to the "left."
Addendum: Found the chapo sub a while later, after a couple instances of folks with bad takes bitching about how awful the subreddit was. Naturally, this piqued my interest, and I discovered the best community on reddit. I even started listening to the podcast, and unironically enjoy it. It was around this time I discovered there were leftist video streamers online too.