Perhaps you should consider your further education/ability to get a decent job before you start getting spun up in the notion that you're going to move out and live happily ever after with your friends/bf.
There are more costs than just rent - remember... Phone, utilities, FOOD! TV licence etc.
As for the job, you can't just go to an employer and say - yeah I want to do 48 hours a week! You know how much difficulty I've had getting a full-time job. "Must have experience" etc. Not only that though, 48 hours a week is REDICULOUS, Jen. I find it hard enough doing a tuppence-an-hour McJob for 17 hours a week some weeks if my shifts are busy/boring. Not only will you have no money for yourself, you'll also not have any TIME for yourself. 48 hours a week will certainly screw up your sex drive (and we both know what that's normally like!)
Then the "what-if's?" What if you split up with lee? What if you and your friends fall out - you need to plan for the eventuality of 1 member of the group being unable to pay the rent - what if someone decides to move out? You could be left completely scuppered.
As for your parents - I'm not surprised they've not taken to this too well, and as some others have said... they're unlikely to warm to the idea at all.
I know this sounds really negative Jen... but I just think its a really bad idea because it could all end in tears.