MY First Time with a non-binary/cross-dresser

After I had graduated high school but before I had left for college: I was hanging out with a friend and a friend of theirs at their friend’s house. For the story let’s call my friend Dan and his friend Charles. We were watching some movie on Charle’s (parent’s) big TV. Charles gets up eventually and says something like, “I have a surprise, I’ll be right back.” He takes off. I immediately saw Dan’s posture change, he was excited and maybe even scared. I was immediately put on edge; I thought it was going to be drugs or guns or drugs and guns: the usual for where we lived.
About forty-five minutes later this chick walks in wearing black lingerie. She had long black hair and smokey eyes, a deep red/purple, glossy, lipstick. She was skinny, small breasts, and walked into the room like model. I thought for a moment that maybe it was Charles' sister - and I was really weirded out that he would send her in as a “surprise” for us. She walked over and straddled Dan who immediately wrapped his hands around her butt, which was rapidly sliding out the sides of the lingerie. Dan began kissing her neck as she pressed herself into him. She looked over at me and smiled, began motioning for me to come join them. I wasn’t sure what I wanted to do, I didn’t know where our host had gone…
She stood up from Dan and walked over to me: her erection was more than “just a bulge” and I figured out then that this was Charles. At first I was horrified and I looked over at Dan who was unzipping his pants (but leaving his shirt and faded blue hoodie on). She/Charles came over to me and touched my head and leaned in close to me and said in the softest voice, “I’ve been wanting to get fucked by you for weeks. I know this is new to you but he’s old to me and I crave new attention.” Something about what she said, maybe how she said… something in the honesty of it seeped into me. I was hard. Harder than I had been in a while. She started rubbing my cock over my pants. “I’m not Charles. I’m Genevieve.”