The truth is, kids learn US history in elementary school (well, uh, that is, they used to), and by the time they reach social studies (which is a stupid name that needs to be retired) they're also starting to feel those pesky hormones, and couldn't possibly care less about ancient history. My mother recalled having complained about ancient history from her high school years in the 1940s.
I don't think I was taught anything about ancient history, I think the social studies pretty much started with the mid-15th century Age of Sail, Columbus' voyages starting in 1492, then various efforts to establish independence by Latin America, then a bit of 20th century (WWI, WWII); by high school social studies had become political science and Watergate was still fresh in memory, while Vietnam had receded (I was of just the right age that I never wound up having to register for the draft).
If I understand correctly, AP means Advanced Placement. If so then it is oriented to the brightest kids who are college bound, it should be more complex.
In my era, elementary school American history was essentially a thumbnail view of key persons and significant events. More detailed American History was a 7th grade course; Social Studies was a re-labeled Civics course; Ancient and Medieval history, once required for college prep track became an elective; Modern European History, IIRC, was an elective.