He doesn't know what 'temporal' means and doesn't write that well. He would benefit from more English instruction.
There are many problems with how kids are taught in school. However, it's arrogant to think that you won't benefit from further instruction at 15 - regardless of how well you think you're doing.
I've known many smart autodidacts, but they're often unaware of their weaknesses. They tend to be less 'well rounded' than those with academically trained minds.