I can't remember what exactly got me into it since I was like 9 or 10 when I started, but I think maybe the first site I ever roleplayed on was one called Kidzworld. I used to use it for a bunch of other stuff, so I imagine that I probably was looking at all of the forums and decided to check out the roleplaying forums they had and must have liked what I saw. I started joining roleplays people posted and doing the classic *walks up to you* style of roleplaying, but as time went on and I roleplayed more and got older my writing improved, so I went from asterisk one-liners to paragraph story posts and so on. Back then, I would roleplay on all kinds of sites and games: Roblox, Nonoba, Omegle, Kongregate, Little Big Planet, Kik, IMVU, Skype, MMOs—pretty much any site with a social element.
I don't think I joined my first dedicated roleplaying forum until around 2015-2016. Since then, I've tried a few of the main ones over the years, but never really stuck around for long. I started doing more novella style posts sometime around 2020 perhaps, and the rest is history.
As for erotic roleplaying, I definitely started way earlier than I should have, probably back on Omegle. Most of my prior experience has been SFW romance and a mix of group roleplays and 1x1's. I think I've written more smut since coming to BMR than I ever have before. It's still my preference to have a mostly story-focused roleplay, but I enjoy the freedom of being able to write out intimate scenes over fading to black, which is part of what brought me to adult writing sites such as this one.