In mid gen 3, around 6 or 7 years ago, and I still have some fond memories from it, with my three favorite pokemon from gen1 at the time being Pidgeotto, Butterfree, and charizard, mostly because I watched the show when I was younger, but I lost the game very quickly, alongside my first GBA, and later got a second one, and ruby later. Competitively, I started watching matches in gen 4, from marriland, but started oplaying in gen 5.
started with a gameboy pocket with red/blue right when it came out in north america although I did watch people play the jap version before that.
I started with ruby. Blaziken and Rayquaza were so sick! Then I got emerald and after that fire red. I stopped playing pokemon... I should start again
I started with the fourth generation. I remember using my brother's game and starting a new game before deleting the old save data. I was quite annoyed...
I played Platinum so much that I still prefer 4th Generation tiers over 5th Generation tiers. I wish that more people were still interested in DP OU. :|
I have to say Gen 3. Not only was it my first generation into Pokemon, I like all of the designs for them!