Switching syllabus and schools halfway through a level

I do chemistry, maths and biology and would like to do computer science which my school doesn't offer because of low enrolment. My current school uses snab a edexcel examboard for biology and ocr a for chemistry. The school I want to go to does CIS for all subjects. From what I've seen online, they don't have coursework unlike edexcel (so pls correct me if I'm wrong). I want to know if the syllabus is similar, would there be enough time for me to catch up with everything and what to expect for CIS. I will start prepping for computer science so I can just try catching up now.

Hey I’ve never heard of CIS but I’d reccomend you go through the spec for each of the subjects and compare with the old one with what you’ve learnt and go over all the things you missed