Welcome! Hope you have fun here at SotE!
I'm pretty sure there are already a handful of fairies. :D In general, I think you can have basically any kind of character you want - races from other fiction, races you've made up, etc. The only exception is god characters, that I think need to be approved.
Also, feel free to say 'hi' in the cbox! And don't be shy about asking questions - everyone here's pretty friendly!