Unleash your creativity - write first! Lose your fear. A published writer told me that her final draft and her first draft don't look anything alike -- not a single paragraph. The lesson - stop worrying about editing when you're in the first draft. It's going to be completely different by the time your done. The act of creating should be fun. Re-learn how to play.
Don't touch it until you've got a finished first draft. Join the "The End" club. Only then should you edit!