Yesterday, the Post ran a story by Jay “Challenge Index” Mathews profiling Bell Multicultural High School in Ward 1, which offers only Advanced Placement (AP) English courses to its 11th and 12th graders. I read the story with interest, not just because the students and teachers Mathews interviews are my former students and colleagues from the years I taught at Bell (2005-2007), but because I was also an “AP for all” teacher, and once struggled…