wreak terrible vengance before revealing their true identity during the school-cafeteria mass date?
Sounds like me.
who has had a full sex change
Beefy.

Honestly though, back on topic.

Get her friends on your side. If you can get their approval beforehand, then thats a step ahead. Especially if you cant get alone with her, let the people know beforehand. I had to do that yesterday.

story:
Spoiler Alert, click show to read: 
Went over to KP's house, had a swim, met one of her friends...who knew me. Apparently i went to school with her for six years. Anyway, we were trying to get alone, so we could talk...:flirt: In a last ditch attempt we opted to go back to my place... She followed us. It took the dogs destroying KP's shoes and us going upstairs to find some she could borrow for us to be alone. I tell you... some people...