Senior citizens of TSRWatch
Also, avoid credit and overdrafts and treat £100 as 'zero' in your bank accounts, so you have far less chance of going overdrawn by accident. And go to Uni to do a course you like, not one that you think will look pretty on your CV.
11-year-old me: Please, please, please just make the most of your remaining time here at primary. Secondary school is nothing to look forward to (in hindsight).
12-year-old me: Stop swearing because you're only doing it because you think it sounds cool...and trust me, you're really not. Start working hard like you were in primary because in hindsight, your laziness now will pay.
14-year-old me: Stop complaining to your friends because it's not their fault you're feeling like this.
Me last year: Revise for your bloody GCSEs god damn you!