I think seeing if you enjoy Chemistry A level is important. I also take bio,chem and maths and im going into yr 13 now but I can definitely say that Chem is very different even in yr 12. I got a 9 in gcse chem too, but I think the questions are way more simple compared to a level. It is also quite a bit of content too, and so is biology and maths requires lots of practice so these three are time taking, so I wouldn't recommend taking English outside of school along with an EPQ. The workload is very heavy. I think the best thing is to see how chem is for the first few weeks, read the specification and see if you still want to do it. Talk to people that possibly do both, they can give a good perspective though everyone is different. If you genuinely enjoy English, you should take it because I think it is important if you like the subject or not, makes you more willing to learn if you do. Also make sure you have good teachers because I find that affects your attitude towards subjects too. Overall though, if you can't decide between medicine and law you should research about it and see if unis will accept bio chem maths for law because I think some do, Im not sure. You don't need to decide what you want to do now exactly but I suggest having an idea of if you want to go into a STEM field or Law. With that being said, I wish you the best of luck for yr 12.