Help! Open gym tomorrow!?

I am a freshman and I have only played cyo basketball for 5 years. We have had open gym since last week and Tryouts are November 1. I am very nervous about going. Only 6 girls go that are freshman and the all have played travel basketball. I also am nervous about running. I get winded very quickly, I am not fat I weight 100 and 5'2. I also play wing. I am just wondering what I should do at the Open gym? Anything would help thank you. P.s the girls that go are also tall like 5'6-6,0.