Do my high school marks matter?

[Personherebb9]

I just don't get the following: "But since I haven't been studying I expect that mark to drop SIGNIFICANTLY. Like at least to around 60%.".  Why aren't you going to be studying? Is the job at your parents business or company taking up a chunk of your time? If that's the case, how do you plan on "spending time studying" for your future education?

Beginning of the year, I was applying to all of the in-person South African unis and eventually I got an academic scholarship at UCT. However, even with the scholarship, living expenses are way over anything me or my family can afford, so that’s when the realisation hit that I wasn’t gonna be able to afford going to uni without making heaps amounts of debt. Hence, why I was looking at alternatives. 

My marks have been dropping, since the only thing that “motivated” me to do well in school was the fact that I had to maintain my avg for that scholarship. I’ve now been more focused on courses and degree plans so that I can finish Uni quicker, so I’ve been lacking in my high school work. It’s also just because I really hate the subjects that I have, I don’t find them interesting, I guess another reason why they’re dropping.

So essentially it’s not that I’m not managing my time, it’s more just because my priorities already flipped from high school to university.