WoW, what a great girl you are!
As others have said, be ready for and dismiss any misgendering, odd looks or comments. You are you and have every right to be you.
It doesn't matter how people react to you, it is how you react to others. Be yourself, confident (even when you are shaking) and polite.
And be careful. When you are going back to your car, have the keys ready to get in straight away. Keep to well lit places.
But most of all, enjoy!!
Oh and remember to breathe