Aha! One place i might be able to drop a quick advice piece, (brand new to pua and prob the newbest of em all). Ill be working on that though
First point, it was brought up theres 2 kinds, quick nutters and last forever nutters. I cant tell you how worried SICK i was before my first time, i was in a situtaiton like you where i lied about not being a virgin, and ongoing lie for 5years. My whole mind was on nothing but how long i'd try and last. Funny shit, because once we got going i started getting scared that id NEVER nut, and then that prabably made it even harder in the end cuase i was thinking about it to much.
I'd blow a load off before you see her to help out, but just about the worst thing you can do is worry about your performance/how long youll last. It will work against you either way. Also i wouldnt be shy with the oral. That's usually almost gaurantee'd to get her to cum, and as long as you get her once she'll prabably be happy enough.
Second, you said your not into her that much.... So who gives a shit? I know hard advice to follow, i know i sure as hell wasnt able to. But once you get through with her you'll probably be thinking the same thing. So atleast keep it in mind.