I'm a year 13 studying geology. It's a very cool and interesting subject. I'm very scared for my exam tho aha so definitely recommend keeping up with your notes and making sure you understand everything when you're taught it as its very hard to teach yourself. As you do maths, you're well set for geology as the maths caught me out being more complicated than I expected. I learnt the other day just 10 days before my exam that SOHCAHTOA was in geology and I haven't done maths since 2019 aha. Make sure you understand basic concepts as you have to use them for everything. And go over mineral and rock types. Make sure you know examples of each type of rock and the characteristics of typical rocks. Good luck!!