How on earth does the way someone present themselves make someone else uncomfortable?
If the roommate has an issue with it, she’ll figure it out and then she can move. I fail to see how that affects the OP or why it means the OP should disclose his gender orientation.
Still absolutely in the camp that it’s not the roommate’s business and no one should feel pressured to disclose any part of their gender or sexual identity if they don’t want to.