Currently I'm in Year 12 doing Maths, Further Maths and Physics aiming for BAA respectively for AS and then AA*A* respectively for A Level. At the start of the year I hated Chemistry only because the GCSEs were bad, as I got 2 Cs in Double Science. Luckily the school I'm at, let me on a trial and they didn't realise I already knew the Physics AS spec.
Now, to the point; I can pick up stuff really quickly and I have no problem maintaining knowledge from the other subjects assuming that I do (occasionally) revise but would it be worth learning Chemistry as an extra A Level for Year 13 with little knowledge of the subject at this moment?