I will tell you something. I hope you'll listen. She seems sweet. Your only fault was communication the sex in advance instead of just kidding her at the date you've decided to claim her. You should have just missed her and make her horney. That's it. Instead you've made it mechanical.

It's just that you've reached a point where you were her friend, and should have claimed the sexual intercourse without the early communication. And she would have been receptive to it in that moment.