Should I resit higher maths?

Last year I was studying higher maths I did ok in the prelim but not brilliant. In the exam in May I felt that I completely messed it up at the time. However looking back know I think I may have actuality scrapped a B. At school we have now changed to the 6th year timetable and I am down in the higher maths class again. I am torn between sticking with a B (if I get it) or resitting in the hope that I get an A.

I hope to go to university to study either computing or accounting and the minimum entry requirements I've seen from both is AABB. The rest of my exams went great last year so I believe I have achieved this. Personally I don't want sit through another year of higher maths when I could be getting another higher but what do you think is best?