1. Register or sign in on Careerpilot and you can save all your choices until you are 21. If you registered last year (maybe at a school) use the email address and password you used last year and then change your details in your account (top right of home page).
3. Consider doing a free, online course in a subject you are interested in. This will look great on your CV/personal statement, will help you decide whether this is the subject for you and shows you are committed to the subject.