Transgender at a Zimun

My cousin is transgender. We are planning on having her at our seder. She was born a boy and became a woman through a series of surgical procedures when she grew up. She now looks and dresses feminine and is hard to distinguish from any other woman. We plan to have exactly two males above 13 at our seder, me and our oldest son. Does Jewish law still consider her male for ritual purposes? Can we include her as a ‘male’ for the third person in a zimmun?