You’ll be fine for A level maths but it’s definitely a bit late for further maths. You might be able to learn the content for AS further maths rather than the whole A level, that’s still a useful qualification to have. Maybe enter for AS further maths and normal A level maths and see how you do? You should definitely start now though, don’t leave it any later. There are loads of past papers available online for maths which is good. I would say go through the content as fast as you can and try to get onto the past papers as soon as you’re finished with content.