I did OCR A and there was quite a bit of maths but it's all the same type of maths so just rearranging formulas and subbing values in. The jump from GCSE to AS seemed ok but the jump to A2 was a bit bigger. It can be difficult, you need different skills to do well in the exams, so if you're only good at the maths aspect then you'd lose marks on the 'wordy' questions, you just have to find a balance. Don't let the supposed difficulty of it put you off, you should choose subjects you enjoy.