The first Shiny I ever encountered was in the early days of my Pokémon career, in Emerald over ten years ago. I was doing post-game grinding in Victory Road, and a Shiny Aron appeared. Now, you might remember that for whatever reason, unevolved Pokémon in Victory Road in that game were underleveled compared to the evolve stuff, while I was also overleveled compared to the area. At the time, I was so young and ignorant, that I didn't even consider the possibility of catching the thing just by throwing Pokéballs. It was ingrained in my mind that I had weaken it first in order to catch it. So I switched into my weakest Pokémon and used its weakest move that was also not-very effective, and I still knocked out the thing. It has haunted me to this very day.
My second Shiny encounter, and my first Shiny capture didn't happen until nearly a decade later, when I was playing Omega Ruby, and I encountered a Shiny Swablu on my way to my Secret Base. I was smart enough to just through an Ultra Ball this time. And so somehow the only two Shiny Pokémon I've ever found have both been in Hoenn, seperated by ten years.