Sleepover :( :( :( really nervouss xxxxxxx?

Hiya :) My mum finally agreed to let me go to a sleepover! Thank god. :D but im really nervous, I've never slept at anyone's house before. And im going at 4pm coming back 3pm. the next day (thats quite long) and when i go at 4pm, when it gets to 9pm were going to watch scary movies, like orphan and drag me to hell. all night, then have a 'midnight feast' im so nervous, what things should i take and look out for? any tips, :// and were sleeping in the living room.. so family might just walk in and out.........