Computer Science Uni course. What to study?

I might do a course in computer science at the local university. Just wondering what should I study at home to prepare myself?
My brother took the course but doesnt think I have a chance in getting in or finishing. So hes not giving me any tips. He told me ages ago they had him learning programming languages that are no longer in use as well as the current ones. Should I start with math? Learning a programming language or what? :/

Learn languages that will help you learn the paradigms.

I'd learn a functional language like haskell or scheme. Chances you'll unwittingly and continuously repeat mistakes in designing software with whatever language they teach you. A FP language will train you control the need for overly complex solutions common amongst beginners.