Hi! I took the same subjects as you when I was in sixth form so maybe I can help.
I would say if you enjoy chemistry then you should take it for year 13! it will be worth trying different studying techniques and seeing if they help and if not maybe get a tutor. But, if you dread studying chemistry and you just can't bring yourself to do it, perhaps take another subject (like Sociology) that makes you excited when revising it.
Also, I should point out that biology and psychology get a bit more tricky (mostly bio). They won't be difficult to understand, just challenging to recall all the information because a lot of things will be added to what you already learned in AS. So, just keep that in mind when choosing a different subject or sticking to chemistry.
Best of luck!