There are 565 episodes of Pokemon. (Yes, from 1997 to now)

Each episode is about 24 minutes long, so if the episodes were to be in real time, only 226 hours would've have passed from start to finish.

But it isn't in real time, and most episodes span 1-2 days, 565 days is about 1 1/2 years, although I like the idea of doubling that for three years better.

So there you go, oldest he'd probably be is 13