Isn't 12k too much?
I mean, you can choose to get a loan for the tuition so you'd only need to worry about accommodation, books and other living costs and I doubt you'll need 12k in the first year. I'm saying first year, because you can get a job while at uni which could earn you more than 35 pounds/week. Also, you can earn more in the summer but that means sacrificing your holiday, which sucks.
Tbh, I think it's a bit douchebag-ish for your parents to say this now... I mean, they could've told you when you were 12 so you'd have more time to seek advice come with a plan for your finances - imo university is a very serious thing that should be talked about from a very early age. Two years is not as much as you think, for ex my parents and I have been saving ever since I was in kindergarten and I still feel overwhelmed by the amount of money I'll need at uni.
Maybe you can find a scholarship/grant that could help you. If you say your financial status isn't good, then there is help available for you, I'm sure.
I think you should focus on getting into university even if you don't save 12k. It is important to get in, after you can find ways to get help with your money. Don't miss on studying because you need to work for money.