AP Tests start the week of the 1st-3rd also according to my school's schedule, and also May would be too late because schools start letting out in the next few weeks, and there are final exams, and it would be impossible for students to make up their homework, quizzes, tests, etc.

Yes, maybe the SATs are held several times a year, but AP exams are once a year and final exams are once a semester, and im perfectly sure that FIRST is aware of this.