High school is often sending the best kidsto college with half their first year done already with AP classes.
So the AP as a means of saving $$$ loophole has been hard closed.
And in hindsight of course that's how it works, both because the university isn't keen on cost savings but also because every student is coming loaded with APs. AP physics isn't "college physics" anymore it's just high school physics and the optional prereq to Physics 101.
Then I took in person classes at 18/19, fixed my GPA and generally did well. The only classes I really struggled with was Japanese and later French.
With Japanese I pissed my Korean girlfriend off, and had to drop it. French I took for a pass/no pass and absolutely failed.
You absolutely can get a BA by 20, but I'd be more interested in WHY you'd want to speed run academia. Sounds really stressful...
1. You want or need to be making money instead of spending it.
Eg, no family wealth involved; you’re paying for everything yourself
2. You don’t enjoy the high pressure (ish), test-driven environment and want to be doing more meaningful work.
Etc. The number of people who don’t want to spend money and time in college might surprise you. I even know some very academically successful ones with this attitude.
Even if you have all the money in the world, US high school standards are very low. With some affinity for reading and access to the internet, one can be learning at a far quicker rate, even without sacrificing social life outside of school.
Many kids in the US already do this via Advanced Placement testing, but some states also allow high school students to take college courses.