I would advise only to do three as A-Levels are very hard. I myself did physics AS and believe it to be the biggest mistake of my life! It was much harder than I thought! Ugh
If you want to do physics, you have to do maths as well! I didn't and I didn't understand a thing!
It seems like you are very science-y and so will be looking to do either Bio, Chem, Physics or/and Maths. The best thing to do is to have a look at some uni courses you may be interested in taking and seeing what subjects they want. Some Physics courses want maths but not necessary physics. Some biochem want chem and maths but no bio.