Struggling to narrow down A-levelsWatch
if you don't do computing a level though, you should definitely do lots of compsci extracurriculars to demonstrate your interest in the subject e.g. learn to code in python to an advanced level, give talks/create a compsci society at your school etc
Probs makes the most sense to do Maths, FM and Physics OR Chemistry. If you find the maths content etc incredibly easy at A level, then maybe do a 4th in Comp Sci as well.