to expect. realize that no one is going to put you on the spot and make you pose by yourself in front of everyone. everyone is there to learn and you will most likely be in a group with individual attention as your coach walks around.
you can wear a bikini- you decide what you are most comfortable in. i wore shorts and a sports bra but some girls were wearing their competition suits. if you feel comfortable in your suit and want to see what you look like as you practice, then go for it. whatever you decide, i highly recommend bringing your heels to practice in.
you will be sized 