1. The class is only as good as the instructor
2. The class is as biased as the instructor (if you write genre fiction such as Romance, Mystery, Sci-Fi, Fantasy, this can be a problem as there is some snobbism from “mainstream” lit people towards genre fiction sometimes)
3. There IS NO ONE WAY OF WRITING.
4. Everything it teaches you, IF it manages to teach you something, you can learn on your own, for free.

If you want to write…START WRITING. Doesn’t matter how old you are—I started when I was 10, and know an author who started in her 20s, and another who started in her 40s. Don’t take a class…study the books you read, and try to figure out what makes you like them (and damn anyone else’s opinion), and what works for you as a reader and what doesn’t and why. Write write write. Then put your own work aside for a few months, and read it again, and figure out why it sucks so much worse than it did when you wrote it. Then rewrite it.

There is no one true way of writing. Different strokes for different folks. A lot of writing classes don’t understand that. Study on your own and develop your own style-don’t rely on others’ opinions on your works. If you keep a critical eye on your own work, and study other people’s works, you’ll get better and learn more, and best of all-you’ll know WHY things work the way they do. You won’t just be spouting “rules” with no inner understanding of them.