Marching band auditions! help?

tomorrow i have marching band auditions and i am really nervous. im about to be a freshmen in high school and right now we are doing summer band practice. but first we have to audition for a spot in the show. and im super nervous. im only a freshman so of course im not as good as the upper cl men but i do not want to embarr myself in front of everyone. i do not know how to at least calm myself at least enough so i can focus on my music and my marching technique.