Need help! Party this Friday, what to wear?

Hey, so I'm 13 and I'm going to my best guy friends birthday party this coming Friday. My usual style is very girly and unique (like i would wear a ballet sweater with a shortish skirt, but then i would wear combat boots covered by leg-warmers). I have to wear some type of sneaker (converse are fine) and pants (shorts are good too) because we are going to play volleyball. I have an hourglass figure and I have (natural) blonde hair that reaches mid-back. I'm 115 lbs. and I'm 5-2 and I'm way smaller than all my friends.