Your GCSE subjects won't have much bearing on your later studies, provided you do the core subjects (science, maths, English language), then just pick whatever for GCSE. It matters more for A-level where you want to aim to do physics, maths, and further maths if possible. So just do whatever you think seems interesting or that you enjoy for GCSE (and ideally that you think you'll get a good grade in). It might be your last chance do some subjects so think about what you might miss doing in future that you currently study!