Hi I'm in y13 and doing OCR Economics, I can't speak for any of the other syllabuses but I'm guessing they wouldn't be too different.
Honestly if you're getting a grade 6 or higher in maths you'll be fine - there is very little maths, I'd say about 90+% of the subject involves written essay style answers. The maths you will have to do consists of graphs with a Y and X axis. They're pretty straightforward, the hard part is remembering them. Apart from that there are a few equations to remember, but they're also pretty simple. You might get asked general things like calculate the mean or median of a chart, but I'm sure you can do that.
I was in your position in y11 as I was horrible at maths and didn't know whether to pick econ, but if it's just the maths you're worried about then you'll be fine, especially if you're passionate about business studies