Yo! I'm in year 12 doing bio, chem, maths and Eng lit. I love biology and chemistry and find them fine difficulty wise. The step up from GCSE to A level chem is quite big as you can no longer get away with rote learning stuff, but as long as you enjoy it and don't mind putting a bit of work in if you're stuck you'll be fine. Biology content is straightforward but there is a shedload of itso that's worth thinking about, but again if you enjoy it it's fine. Maths again is alright, and in fact I enjoy it more now than at GCSE, but I also know people who hate it now so probably think carefully about taking it. Physics, based on what friends have said, is harder than maths, and it's also worth noting that many schools strongly encourage maths alongside physics. That's not to say you can't do physics without maths, but it would make the course more difficult and it would be worth speaking to your teachers about taking physics without maths. Have you thought about starting with 4?