I have a friend and her daughter goes during a school morning and then to school. I'd ask your mom if you couldn't get a 2:30 or 3:00 slot and be picked up from school, etc. if necessary. It's one day a week. I don't know what your last class is and how well you're doing, etc. but it's just a "doctor's" appointment, it shouldn't be too embarrassing or anything if you got up and left a little early one day a week.

I had a 3:30 appointment that got backed up to 2:30 and I use to have to leave work Noon-1:00 on Wednesdays to get there in time. It's a bit embarrassing and weird the first few times but then everyone adjusts.