I have played all three pieces in workshops and piano parties, but not without errors!
You will make mistakes, you are human! It is learning to play through those mistakes and not letting them put you off the next bit, that is the skill. You can not learn a piece to such a level that you go into an exam 100% confident that a mistake is not possible, so embrace the little errors, because through them you can show to the examiner how well you can continue anyway without a slip affecting the musicality of the rest of you performance.
Don't get too hung up about tempo either. Some of the markings are a joke! The Grade 6 piece I am learnng at the moment has a tempo marking that would be way too fast, and the two professional pianists I watched playing it on Youtube are taking it much slower and it sounds great at their speed.