Since 2012
Nice. And it is your first bitcointalk account? I find it hard to believe in. Also I want to point that this is thread belong to Bitcoin Discussion forum, not off-topic section. As we clearly are discussing bitcoin related facts here. Any mods here?
Anyway, I first heard about bitcoin in 2013 but then it was just a minor 'news'. later I created my account here early in 2014 and since that time I am always here! Bitcoin revolution!