You can write from a fiction or a non-fiction angle. Just have fun.
Deb, could you please clarify? I always thought the stories submitted to the Challenge had to be fiction and that if you write from a first-person perspective, you have to include a footnote the clarifies the entry is fiction. Has this changed?
Any kind of writing is acceptable--fiction, non-fiction, poetry.
If you write from a first person POV, you may include a footnote. It's not required, but some people prefer it, lest their writing be taken for a true account. That's up to you, though. Deb prefers it, as a reader, and I don't--but the footnote itself wouldn't enter into the judging process in any way, so it's totally your call.