What to study at sixth form if i want to work in film?

I'm 16 and doing my alevels in September I have picked my subjects but they are still flexable to change as they are not completely confirmed until September I want to work in film production behind the scenes but I seriously do not know how to get there please Help would it be better to study Media as well as my other subjects or take the Media Studies OCR National Award? and what would be better for university? Would it be good to go on to a apprenticeship PLEASE HELP??