All the time Bobby is in the shower you are steeling yourself. The time to come out is now, it will just get harder if you wait, and if you want this relationship to get off on the right foot you need to be honest. But you don't know how Bobby will react.
Bobby comes out of the shower smiling and wearing a purple bathrobe.
You stumble into "Bobby, my pronouns are she and her. I'm trans."
Bobby is confused, then dawn breaks. "Oh, I didn't realize you didn't know. Bobbi with an i! I'm a girl too. That's why they put us together! They didn't tell you that?"
"No"
Bobbi rolls her eyes. "Typical. Anyway, we're sisters, OK, sis?"
"Sisters" The two of you hug briefly. "Now," Bobbi adds "What's your real name?"
"Morgana"
"Hi there, sister Morgana."