I can confirm that my database also thinks you posted your first work in 2010 :) I'm pretty sure that's right, because I worked on your masterlist last year, so I was poking through your LJ rather thoroughly!

Other authors I think began in 2010 (but who didn't participate in the fest this year) include khasael, tigersilver, josephinestone, kjp_013, sara holmes, and 0idontknow0.

Also, if we consider femmequixotic and noeon as a unit, I think they posted their first fic together in 2010, so maybe that should count!