A few years I guess? I started becoming interested in singularity ideas from reading the LessWrong forums back in the 2010's.

I was more optimistic ten years ago, but I'm more sure of it happening than before. Just that it seems to be much "messier" than I hoped.

I also never seriously considered the possibility that aliens might be the harbingers of it, before a couple years ago. But there's still AI, and institutional collapse to worry about.