I want to study Zoology at univeristy. I have been advised to take Chemistry and Biology as A Levels. I am very fond of Biology and have no doubt I can get good grades in the subject. But, I haven't studied Chemistry since I was in year 10 as my new school didn't offer it at all. This means I haven't done a GCSE in it, but I have in Biology. I am planning on taking 3 years to do my A Levels and am taking them as an external student (I already have a centre for the practicals). Do you think this will be enough time to learn the subject well enough for a good grade? I only have a grade 5 in GCSE Math, will the maths in Chem A Level be too difficult for me?