This is such a coincidence.
I've also picked Maths, Biology, Chemistry and I'm struggling with the last. It was initially Government and Politics then I changed to Economics because it would go well with Maths. Now I'm completely clueless I'm considering Art because I got an A. I think I might to English as well?
Anyway, most people I've spoken to have told me to wait until I get my results to see what I achieved the highest in. Also try going their open days;D