How many years of college does it take to become an orthodontist?

I heard that it can take up to 15 years of college, but I’m a sophomore in high school now, and I’m taking ap chem, and I also plan on taking ap bio and ap physics in high school, so if I take these courses and pass them, does that mean that I won’t have to go to college for so long? Also, what other classes do orthos take in college? And what are some other ap classes that I should consider taking in high school if I want to be an orthodontist?

Generally, 4 yrs undergrad + 4 yrs dental school +2 yrs of ortho post grad.