I studied English, Law and French at A-level and am currently studying English at uni, though my dream career is in film too. If you want to study film at an university, you will have to prove you have an interest in film in your personal statement - so this would be things like online publications, events, online courses etc. relating to film.
Most universities will also ask you to provide a portfolio of your work which is probably something you should start now if you haven't. Just write a script, get your friends/family to act for you and edit it as best as you can. They're not looking for Spielberg-level of quality but just proof of interest. Your dreams are still in reach.
Hope this helps!