I understand you can resit gcse maths as an adult.
I got a d at school. I was pretty much a b student in terms of internal exams, but was a bit of a twat from year 9 up and didn't bother to do the coursework - which counted for a %age of the overall grade.
I can't say not having it has hindered my career... I have professional qualifications (aca and CTA) which require maths skills but of course if I wanted to change career I expect it might course problems - however at present I don't.
So it's basically a vanity project - I want to see how well I could do if I applied myself to it. I was always told maths wasn't my thing, and although I wasn't bad at it, I was very strong at humanities. But is that a bit of a shitty reason?
So Aibu? I would self fund it, if that makes a difference.