Go in there and hold your head high. Be proud of who you are. People who transition are a tougher, wiser breed of person. We've endured things that cisgender people can't dream of, and seen the world from both sides of the gender divide. We are strong, intelligent, and competent.
You're as good a person as anyone in there. They should be concerned about what you think of them. Don't one of them look at you funny, or there will be no way for them to redeem themselves in your eyes. Go in there and be your fabulous self. Don't allow yourself to be judged..