The sad thing is that in the first two years of college students will retake the same courses they just took in high school. Only in America. My son, the MD, took part of his clinical rotation in England and he was two years older than his classmates because they only go ten years there. Our neighbors to the north, Canada, have only 10 or 11 years of school depending on the province.
The College Board, owners of the AP and SAT, has had their College Level Examination Program, CLEP, since the 1960's, yet few parents and teachers know about it. They have 33 0f those exams and it is very possible to take the course in high school, and then CLEP exam to get college credit. It is easy to start college as a junior right out of high school.