I scraped a pass in maths at O level in 1977. That is probably more than you need to be a pilot. All the maths you use is common sense. You will be given 'rules of thumb' to work with through your training - none of them are complex.
Interestingly, many people think that people with a good scientific education and skills would make the best pilots. But it's often the other way round. From my experience as a RAF QFI, spatial awareness is most important and it's the artists and not the scientists which tend to have this. When I think back to my previous students, the best ones were not mathmeticians - in fact far from it. Of the three I can think of right now, one had come straigt from school with mediocre geography and history A levels, one had been selling second hand cars and one was a piano player! I did have one good guy who was a marine biologist - which is sort of a science - but he had spent most of his university time diving and surfing. One guy had a physics degree from Oxford. He spent all his time trying to understand the mechanics of what we were doing and the more important stuff just passed him by!