Technically, he was 29 years old when it happened. Let me explain: The Pokémon series started at April 1st, 1997. The XYZ finale debuted on January 21, 2017. Ash was 10 at the start of the series. The time difference is 19 years, and 8 months. And in the first Pokémon episode Ash just turned 10. But have you ever heard of the term; Cartoon characters stay the same age. So maybe he was 10 when it happened. (I get that it's a meme so don't call me a nerd pls)