Huh. First of all, I'd want to finish school before going on a Pokémon journey. Then, we have to picture 'going on a Pokémon journey' as if it was something extremely common like it is in the Pokémon universe. Most people who say 'lol my parents would never let me go!' are assuming their parents would think in a real world way, when it should be considered that we would be in a completely different reality.
Yeah, so like, Satoshi went when he was 10 years old, meaning he was far from having full education, which might just explain why he is so stupid.