There’s no harm in asking, but starting a new AP class is more complicated than just talking to your principal and him okaying it. He’d have to a find a teacher to teach each new AP class and the teacher would have to do a lot of work to prepare for the class and meet College Board’s requirements. These are the steps to start a new class: http://apcentral.collegeboard.com/apc/html/how-to-start-an-ap-course/how-to-start-an-ap-course.html.