I’m in a very similar position, as I am wanting to apply next year for physics at oxford but i due to a timetable clash, i cant do fm in y12 so i am self teaching the entire A level syllabus this year, to join the fm class next year, with my school being aware of this. This is also the way my school teaches fm. Right now i am studying Maths, Physics, Chemistry and German, and will complete further math a level next year