To be frank, I was the exact age and target demo when Pokemon first came out and I recognized it to be a tedious affair after Gold. Two of those games were enough for me (collected the FULL Pokedex in both Red and Gold) to get the gist and not want to ever play another. And from what I have seen of the modern iterations the game's core has not really changed much, and the Pokemon keep getting stupider. The trainers are getting hotter though.
I don't think Pokemon is a good game. I don't think the mechanics are good and I believe the core gameplay loop it teaches to be a negative one. It feeds the part of the brain that needs to fulfill and complete things and has effectively bred a generation of nostalgic hoarders. True.
that being said I really enjoyed Gold and have very fond memories of the time I spent playing it over that Summer
but I know now to let those memories lie, that pond is better left still
Pretty much the same for me. I was a dumb kid, so I bought both Red and Blue because I thought it was a two part game (I thought the "campaign" continued from one cartridge to the next somehow). Silver version was amazing because it was friggin' huge: 100 more pokemon and double the area to explore, plus an internal clock with day/night cycles and pokemon mating. I never did catch 'em all in Silver though. There were too many new and complex ways to get some of them, I only had one friend with Gold, and the legendary dogs were insanely hard to capture.
A friend and I bought Ruby and Sapphire when we were too old to still be playing it, and it was fun, but it had definitely lost its magic (both the game and the universe) by that point. I never played any of them after Sapphire version. It's really hard to contemplate how into it I was though; I literally fantasized about having
real pokemon, which was a terrible affliction since they aren't real (I had a similar thing with Yoshi and Tails).
I did replay Blue and Yellow at some point in early adulthood and still enjoyed them somewhat; however, using Dodrio mode on Pokemon Stadium helps speed things up so that it's more bearable. That said, I don't think I could enjoy it much now given the lack of imagination I have as an adult, the simplicity of combat, and lack of anyone else playing it (That's a big part of it. You're into the same thing as everyone else at the same time - the same reason Pokemon Go! was so big a four years ago). It's one reason I never gave Pokemon Uranium a chance. I downloaded and launched it once.