Hey
i know exactly how you feel, you sound just like me when i was in your position! I am hopeless at maths, at GCSE i was in Top Band, but bottom set (if that makes sense to you), so I took the intermediate paper, but i did get a C, i did have to work REALLY REALLY hard for it. But to be a pilot, you must work really hard, so just believe in yourself, and come results day, im sure you will get a pleasent surprise, I wAS as chuffed when i got my C in maths! Good luck for your future studies, and if you dont get a C, then resit it, maybe part time, cos you have a few years until you train full time to be a pilot, im sure
