I wish the best for you but I'm concerned. Any time someone will go to meet a stranger from the internet, especially just for sex, I'm concerned. She could rob you when you get there. I wish you would find someone local, if you want to know the truth.
Frankly (if I were you) I would not assume you will go somewhere to be alone that first day or night. Instead, If it were me I would bring someone you trust with you, and hang out with this stranger for a few days in public places, before you even think about having sex with them.
Do you know if she is married? How much do you really know about her? Have you verified it? Have you seen that TV show, Catfish?
Something about it doesn't seem right to me...and that plus the ASD tendency to be easily fooled...makes me worry for you.
What to say at dinner would be the least of my worries. She sounds aggressive and will take the lead, for sure.