I've known a few people who've tried the 'start at a 2nd semester course and make up the rest later' trick. Of those who actually managed to convince the school to let them do it, nearly everyone who's tried regretted not taking the first semester class first.

I've had two creative writing classes and both of the teachers (and classmates) didn't mind Sci Fi stories -- the key is to avoid large amounts of 'treknology'. Still, I may have been lucky in that respect.