If you intend to go into Finance and Accounting then definitely take it. Why won't you get any higher than a 6, though? surely you have nearly a year to improve? I would assume that Finance degrees either require or have a strong preference for maths, so don't try to escape it. Work hard at your GCSE and try to improve your grade. At the end of the day Finance is (obviously) going to be filled with a lot of maths, and I think if you don't pick it now then you'll regret it later down the line. Just work at A Level and you'll be able to cope (especially with a lot of the AS stuff which are just high-end GCSE topics).