Complex sentence: In American Samoa the typical Junior/Senior prom is held in most of the schools, an exception would be one of the private schools, which lets even 8th graders, freshmen, and sophomores participate in prom.
Split into simpler sentences: In American Samoa the typical Junior/Senior prom is held in most of the schools. And exception would be one of the private schools, which lets even 8th graders, freshmen, and sophomores participate in prom.