Welcome to the SBK family! Testing is SBK is a recognition that you have already achieved what you needed to achieve for your kyu rank. The testing is a recognition of that achievement.
Practice the test slowly, because you will move quicker during the test itself. Make sure you keep on breathing during the execution of the technique. Take a deep breath at the end of each technique. Take the test one technique at a time and once you are done with that technique forget it and move on to the next. Most importantly, enjoy the moment.
Congratulations in advance!
ps.- Everybody is nervous before their test, then the moment arrives and you are only in that moment.