I started a decent bit later than most "Real" fans, soon after yellow came out. However, if first pokemon means first pokemon I obtained, that would actually be Eevee. See, back then, when I was a wee lad, only just ripping open my first pack of pokemon cards and sharing in Ash's mighty adventures, we were quite the poor family (Still are, I s'pose) and my sister and I were sharing the game. She started it and was rather posessive, but one day she went on an excursion whilst I was sick, so I seized the day, and, blindly staggering about a game I'd never played, managed to talk to some weird dude in a building.
My first STARTER was Squirtle, as we got red version a few months later.