Make note of your strong points and weak points (that is a strong point) I like to say I'm a perfectionist and go over work twice to make sure it's perfect and then go on to say how that may take a bit more time, but it's important to me that I make sure everything is in order. Deep breath, try not to put too much pressure on this one interview and know there are loads of other doors open to you. Just do the best you can, maybe look up potential questions that may be asked, or questions you can ask. If it's any kind of reassurance majority of the population is nervous about job interviews. I remember on one occasion I literally had a full on panic attack and cried in my car before hand. At that point I was just doing it for anxiety exposure. Somehow got hired, but fun times lol.
Best of luck to you, I hope you do great!
"Though my soul may set in darkness, it will rise in perfect light;
I have loved the stars too fondly to be fearful of the night."