Ask for a lady who is sensitive to special needs. Seriously, it is what I will be asking for at my next visit.
That will make it so much more workable. When they ask you to change into the gown, ask specifically what they want off.
Ask for details. Be calm, it will be just fine.
They are going to feel the sides of your breasts for lumps. They will check inside with a little weird gadget. Oh, and you will pee in a cup. It should be only weird, and fine a little while after you are done.
Goodluck and Don't worry, Be Happy