anyway TS, put it down in b/w so that your friend wun accuse u later of any wrong doings. must disclaim that u are just a newbie, so dun expect too much of you.
if u are going ahead with this shoot. be sure u arrive earlier at the venue to test out some shots so u wun panic later.
try to shoot in manual mode (experiment what white balance u can use, ISO to use, aperture + shutter speed to use) to have consistency in your shots.
do shoot in raw format instead of jpg in case u need to process the photos.