My teacher and I are really close, and he said he considers me his friend more than a student. He's 24, and I'm 14. I really like him, but is it weird? It's only 10 years, and I've seen marriages like this work out

That's an unprofessional thing for any teacher to do. Once you are 18 then yes, it would be an appropriate relationship, now however, you are a minor and that type of thing is unethical, could be borderline illegal if it goes any further, and just creepy.....until you're 18, then all's well!