Choosing A-levels for Computer Science, Law, and Medicine

I am beginning to consider different degrees and career options. I cannot decide between computer science, law and medicine at university. Would A-levels in maths, further maths, chemistry and English/history enable me to study all the degrees in university for example at Oxford?

If you get the grades required then Yes. From Oxford's website.
Medicine; Candidates are required to achieve at least a grade A in both Chemistry and at least one of Biology, Physics, Mathematics or Further Mathematics. So Yes.
Law; 3 A levels at AAA. An essay subject can be helpful when completing this course but is not required for admission. So again Yes.
CS; A*AA including at least an A in Mathematics, with the A* in Mathematics, Further Mathematics or Computer Science.
Those taking Further Mathematics A-level or AS-level are required to achieve at least Grade A. So again Yes.