How to deal with pre race jitters?

we are having a time trial on our cross country team to see whos on varsity i am really nervose because im the 7th best on the team and only top 7 is on varsity my pr is 18:27 the first two runners ahead of me are about 1 minute faster the other guys are varsity guys are running 16:00 or faster we have one guy behind me who runs 18;30 i need tips on how to calm my nerves i just really wont to be on varsity i need any advice