I've lived in a dorm for a year with 25people, then another one for a year, I've lived in private residences with 10people, 4people, landlord male only accomodation etc. I think its cool.
If you're male, do not live with women, they are an utter nightmare! some are darn cool though, there are psycho cases in any sex.
A male living in male only digs, is v.cool, and vice versa. I got kicked out of one female landlady residence, in sept, after booking it in feb. I lasted 1.5weeks! I moved next door for a few years with a guy landlord which is uber cool.
You should be happy that they are enthuastic! How would you feel if you signed the contract, and they turned out to be horrible. Also - you are worried about grime? - buy some thick kitchen gloves! I hate washing up/cleaning, but give me some gloves, and I'm happy like a pig in s**t!
You SIGNED the contract - either get someone else or live with your decision. There should be a legal 7/14day cooling off period that applies - get in quick and find out! and more importantly see a solicitor/internet, and write them a letter saying you want to back out.
LEGALLY
With any contract or sale which is concluded away from the trader’s normal business premise, you must be sure you have been presented with clear written notice of your right to cancel, at or before the time the contract is made. If you have not, the contract is legally unenforceable.
This notice, which cannot be in the form of small print, or otherwise disguised, must also provide a cancellation form and advise you on how and to whom a notice of cancellation is to be made. You can use the cancellation form provided or a simple written notice, as long as it is clear of your intentions. And as long as you have posted your notice of cancellation before the end of the cancellation period, it doesn’t matter when it is actually received. For this reason, it is always advisable to send it recorded delivery.
http://whatconsumer.co.uk/cooling-off-and-cancellations/