First of all, if I could offer a piece of advice, please don't grow up. It is a trap. If you have no choice, make sure you're well aware of the various traps set by society and other adults.
1) £-30 is absolutely a number you can have in your bank account.
2)You will always inexplicably find yourself in a queue at the post office.
3) Taxes are emotionally draining.
4) There is no point in summer once you're in full time employment.
5) You will waste so much time talking to customer service representatives.
6) Wine helps.
7) You're going to need to learn how to make more than two dishes.
8) Problems don't just fix themselves.