It’s way easier to start revising early, it means you just have to do little and often. Otherwise you’ll wait until exam season and have to cram all the GCSE content and that’s tough.
Don’t overdo it though, no need to spend like 3 hours every night, but just keep reading over notes, maybe start making flash cards or whichever revision resources work best for you. It makes it so much easier when you come to the serious revision in Y11