First brony? The first pony song I listened to was "All-Powerful Trixie" by Not A Clever Pony -- download date: 8/13/2011. --I believe I was watching the show and reading fanfics even before this. Equestria Daily was running for at least a few months before that.
I used to watch G1 as a child, does that mean I was a brony even back then? As a second though I may have been destined to start watching FIM sooner or later.
I do believe the show was first shown around 10 am on a Sunday, so I could imagine sitting around, being bored on a Sunday morning, channel surfing, and coming across MLP: FIM, and thinking, "Whoa! This isn't my parents ponies!" On a side note, it just so happened that I was writing a long letter to my friend on that day. It seemed I was talking to her about cats. Hmm . . . Nope, no connection that I see.
I been a fan since 1989 where I saw the movie and Bright Lights. And I did not hear about FiM before last summer.
It completely depends on the definition of "brony". If it's just a fan of MLP in general, then it would've been fans of the first generation (I'm sure that there was at least one older fan of the show). However, the term "brony" was coined when FiM started getting popular. So if only fans of the latest generation are bronies, then it would be the people on 4chan who started the craze.
I watched one of the old movies. No idea which. No idea why. Loved it. But atm, I can't STAND previous generations. I don't want to be caught watching tha- holy shiz is that how closet bronies feel?