I wouldn't have thought your past will affect this and I think that once you've done this first job you'll feel so much better, you just have to get through it.
Preparation is key and like someone else said, you could make a list of all the things that you think could go wrong. Get it clear in your head exactly what it is you'll be expected to do, picture yourself doing it and doing it well. And remember to breathe. Good luck, you can do it