Excelsior is a legit school, but I would assume you would have to be signed up with 12 units at Excelsior. I had to do the same thing for my son, as he is a full time student at the local university. My provider (Kaiser) needed a signed form from the local school confirming he is a full time student. If you are going to Excelsior and taking clep exams, I don't think that would qualify as full time. You would need to get with admissions.