Good luck Greg
Don't worry too much about all-guys you'll meet people from other flats! Go open-minded and if it turns out bad you can always try and change it.
Don't worry about what to take either (apart from like bedding, that can be tricky) cos you can always go out and buy a fork!
And don't even worry about over-thinking! Uni kinda sprung up on me too and I just swanned in thinking everything was going to be easy and okay - it's good to mentally prepare for uni, just go in looking to be sociable and have a good time!