I agree, talk to your coach. She/he may have some idea of who you're up against in this comp, what the required elements are and whether your placement really matters. Sometimes my coach wants or needs me to take a chance on elements that aren't where I'd like them to be, and sometimes she prefers to substitute something easier.
Regardless, I've never gone into a comp 100 percent confident in every element, and I doubt anyone else in your group is either. Good luck!