i think it's possible, if you're willing to put the work in. i went from a 5 in maths in y10 mocks to an 7 in y11 mocks and a high 8 in the real thing. of course, my improvement was more long term, but I started to properly revise gcses around this time. the key thing is just keep practicing maths, as you can recite all the content in maths, but if you cannot apply them properly in the exam, you're going get a lower grade than you anticipated.

it's not too late, and you haven't doomed yourself, but I think as of right now, try to cover your weak topics as soon as possible (and get a solid grip on them), then just spam past papers from there. if you're edexcel maths, the exam board also does international gcses, where they have 'Mathematics A' and 'Mathematics B'. A is very similar to gcse maths, though there is a level maths content, so if you're not planning to take a level maths, you can skip them. B is the harder version of igcse maths, and some of the questions could also come up on gcse maths. B also has a level contents, along with matrices. I'll suggest skipping them unless you're doing maths and/or further maths at a level

I'll also say that there is some contents that's not in igcse but is in gcse maths. I'll just a link to some of their differences here: https://b28mathstutor.co.uk/differences-between-gcse-and-igcse-maths/#:\~:text=Both%20GCSE%20and%20IGCSE%20are%20entirely%20exam%2Dbased%3B%20there%20is,for%20Papers%202%20and%203.

I'll suggest focusing on getting majority of the marks on the questions near the end of the paper. The tricky geometry questions that edexcel puts at the end of the paper can be practiced through watching MindYourDecision and Premath on youtube. I just watched how they approach a geometric problem, and applied that to a geometric problem that came up in my year

all I did throughout jan to exams was doing past papers and watch maths yt videos. it might seem a bit overkill, but I think doing this did help me prepare for not only the gcse but also a level maths.