Hi Bro, if u dun wan, u can pass to me - i cute also haha (just joking).
Anyway, seriously, dun tink so much, dun expect anything (long term) and just go for it. She has not yet directly say she wants to do it with you so u can just have fun teasing & flirting with her....the "tension" is fun too - but dun take too long, a fire left too long will die off.
If u eventually do it just make sure u use CD. U should also guard against developing too much feelings for her - a little bit is ok as it will enhance the love making but not too much until u do crazy things. Just take it as it comes.
Side note: for some ppl, making out with another man's wife is an additional turn on
Good luck!