Congrats.
I've posted a bit about Bath and the accommodation I stayed in in
this thread.I'll also add your question about the social life to the FAQs.
Some of the Maths modules are difficult. The first year wasn't very difficult, though there was one completely puzzling module (Algebra 1A) and another one which isn't part of Econ with Maths. It was kind of settling in, bridging the gap between A-level and degree level Mathematics and you didn't need to be in the library 24/7 for it.
The second year, so far, seems to be noticeably more difficult. Algebra 2A is more confusing than Algebra 1A, and Probability has jumped a bit as well.
I don't really like algebra or mechanics so those bits of the course weren't really interesting but the other bits have their moments.
As for the social life, there are
over 80 societies (with a few more being added this year like a Live Action group, and a friend is hoping to set up a Bridge society). These societies have socials which can be pretty interesting - like the comedy society is going to see a few comedians from Mock The Week, but sometimes the socials are just getting together and going to a particular bar/club.
There are also a lot of people involved in sports and they do socials as well. It's a good way to make friends, stay fit and stick something on your CV.
There's almost always something going on at the centre of campus - perhaps some SU officers (Students' Union) are there for people to talk to, or a society is raising money for charity or selling things, people advertising theatre productions, companies like EY setting up stands and talking to people, occasionally some singing and dancing.
The SU has a few things going on during the week - a quiz and a few themed nights. There's also happy hour and some snooker tables/darts, which are pretty busy most of the time! They also show football matches/rugby from time to time, and the atmosphere is incredible, though it can get really, really packed.
In town there's a nice ODEON Cinema as well as a smaller independent one. There's also a Nandos and some other fast food chains, a place called Komedia, as well as loads of shops and bars (Belushi's and Molloy's seem to be popular). There are a few options for clubbing, like XL, Bridge and Weir Lounge (which may have been renamed). Bristol is not too far away so if you wanted to you could hop on a train and go there for a night out.
Almost all of the people I've met are nice/friendly people as well.