You'll do fine as long as you don't over think it too much. Sometimes I've seen people (younger scholars in particular) get completely intimidated by their surroundings. Don't let this happen to you. You worked hard, and you have every right to be there! These are your peers and you don't need to feel inferior for a lack of experience. Be confident, you probably know your particular topic better than most people in the room, so be sure of yourself. Best of luck!