My first two cards were a Meowth and a Geodude. I still have the Meowth but I traded the Geodude at some point :( I think my favorites are the Meowth, my Mewtwo from my history teacher, my Reshiram EX from my friend, and a random Kabuto card that happens to be in German.
Given that most people get Pokémon cards in packs of, at least, 15, and their first is usually a whole deck, I dunno if you could really get a lot of people who remember their first card, I definitely don’t! My favourite is definitely Growlithe, but I have no recollection of what my first cards were really, it’s too long ago!
Oh man Growlithe is one of my favs too! That was one of the first Pokemon that my friend introduced me to. Those were simpler times… But about the cards, yeah, that's true. I didn't actually start buying cards until recently, so my collection hasn't increased by packs or anything