We've been reading the submitted stories. (Thanks for submitting!) I read one recently that started with ...a dream. In general, starting with a dream is problematic. This is because the beginning of the story is a promise of what's to come. If the story starts with skiing polar bears in a dream, there had better be something related to skiing polar bears at some point in the story. In addition, dreams are inherently irrational. Beginning with a dream promises irrationality in the story.
Thus, consider avoiding dreams in your story. Good luck whatever you decide. :)