Assuming I wasn't just an Ace Trainer, I'd probably either be a Pokemon Ranger (Probably in the Almia Region, since that's where the school is) or I'd be a Professor's Aide, likely either in Hoenn, Kalos, or Alola. Most likely in Hoenn because I like Professor Birch's research the most.
"No matter where our destiny leads,
I'll be there for you,
Always come through,
And that you can believe."