a levels for film HELP!!! Watch
Take the subjects you enjoy the most, and those that will stretch you. And make films in your spare time.
If you want to direct, start now, learn as you go, start small but just start doing it. It won't matter if you have media studies or not. Honestly.
look up the career paths of some of your favourite directors - wherever you are based, so UK - UK directors and see what their career path/body of work has been.