Doing this combo is completely fine. I started Year 12 with Biology, Chemistry, History, and English Literature, and I dropped Chemistry after the first term once I was pretty confident I wanted to do History at university.
Just a word of warning, though: I loved Chemistry at GCSE, but when I started A-level, while I was enjoying the theory, it turned out to be much more maths-heavy than I anticipated. It was basically all maths for the most part, and that threw me off.
I loved History and English, and I enjoyed Biology too, it felt like a better fit for my skill set. It’s a content-heavy, memorisation-based subject, and since I was studying AQA, it even involved essay writing, which made it feel more similar to my essay subjects. That might not be the case for you, but since you mentioned that you dislike maths and struggle to study things you hate, I’d keep that in mind when you start Year 12. Be ready to reflect on whether Chemistry (and even Biology, if you’re unsure about it) is truly for you.
That said, Biology, Chemistry, and History is a perfectly solid combo! It shows you’re a well-rounded applicant, whether you go down the STEM or humanities route. And doing an EPQ demonstrates great research skills.
Just make sure you have some back-up subjects in mind in case Chemistry or Biology doesn’t work out the way you expect. For me, that was English, I originally thought I’d drop it, but now I’m predicted an A and I’m so glad I stuck with it over Chemistry. It suited my strengths much better, and I don’t think I could’ve pushed through the maths in Chemistry since I just didn’t have the drive for it.
Hope this helps!