This was my assumption, that she was referring to her current twitch. It places the end of the search to 2019 April, when she started her current twitch. Or at least that's the date I used, I was wrong about the stream date earlier so IDK. She said 3-4 years ago from 2021, and 2016 seems like too long ago. But even in the event she meant her other twitch accounts, the earliest clips I can find from them were from 2018, which meant she could have been referring to when she started STREAMING later on those accounts, not simply their creation date... I think 2018 is most likely to be when she streamed on chaturbate, probably the first half of the year, since the last half she was on twitch.
A personal tinfoil hat theory of mine is that she disliked the exposure of being a camgirl, or something, but enjoyed the streaming/audience dynamic, and since she has been a twitch viewer for a long time, maybe this gave her some incentive or motivation to begin streaming on twitch.