Usually white belts don't do much at gradings. I do TKD, but usually white belts just go through the basics, one kata, and are asked a few questions. They are not allowed to spar yet. My school does breakfalls, basic jointlocks and one step techniques, also for white belts. But your school maybe different. It's normal to get nervous. I have tested many times, and I still get nervous. Just get in there, and do your best