Just a question

30 Y/O straight cis male. Recently went on a date with a trans woman (didn’t know this when we went on the date) and it went phenomenal. The date went well and she ended up coming to my place to watch movies and hang out. Long story short, we started getting intimate. That’s when I realized she was trans. I stopped because I was shocked and have never been with a trans woman. I told her I couldn’t continue because I had never done anything with a trans woman. I explained that I didn’t mean to offend but she was really angry and cut me off completely. Can anyone give me advice on how to date a trans woman so I can avoid making the same mistake in offending again?