In my personal experience, I first heard of it 1 year ago in a online forum game, people sold gold for Bitcoins, around March, gave it no importance at first. Now im kinda utterly commited to it. Really an interest subject of study.
I first heard about bitcoin in 2014 from a college friend who was always busy with his laptop in college and I was not interested in that moment, I was attracted to bitcoin a few months ago after seeing my successful friend.