I consider my first Pokemon game to be Diamond, actually, in about eighth grade.
I had dabbled in RBY, Gold and Silver, and trading cards as a kid, but never really became hooked.
In Diamond, though, I found both an intriguing game and a journey through nostalgia.
I remember using my entire team (okay, a Shinx, Chimchar, and Starly) to barely manage to catch an Onix, a poke I remembered from my childhood, who went on to be the MVP for about ten minutes. (In my defense, Monferno is awesome)
Later, I struggled through the Elite Four, desperately switch-healing and using every last revive in my bag, only to face the champion. Somehow, we pulled through.
I played via FC for awhile, journeyed through Hoenn in Emerald and raised a team of pokes.
Then, I discovered Smogon, and learned that every last poke I had was horrible. (Though I probably should have seen it coming with Ledian...)
Since then I've been struggling to shake off n00bishness, discovered new tiers (WOO LC), Nuzlocked, Scrambled, ragequit Nuzlockes, joined CAP ASB, and generally become one of the largest closet nerds in the world.
It's been fun, and it continues...