That is a dilemma. Forget about the dress and focus on what you can do. Don't wear makeup or jewelry. If your hair is long enough, pull it back into a ponytail or bun. Many members have said they get by through "underdressing" or wearing something underneath that suits them. You could wear a pair of boxers or boy briefs under the dress.
The key is to remember that they don't know your secret. They think you are a girl, but you fooled them. You are just another guy in a dress! It will be hard when they are treating you like a girl. Just smile because you know the truth. Do try to have fun with it. 🙂