predicted grades:

so this a lot of diffrent questions in one:
I want to go to edinbrugh uni to study computer science and the minimum is ABB, I think i can get an A star in maths but for my other 2 alevels one will be a B and one will be a C (of course this is a guess). Now the reccomend is AAA but due to covid and just usual uni entries im confused if an astar in maths will help me and im also thinking of redoing my gcse maths to raise it from an 6 to a 9 (yes i have an average maths alevel grade of an a and i got a 6 at gcse so just saying you can do it). Anyway any advice on predicted grades as well and any general grade advice for admission next year?

The minimum entry requirements for Edinburgh are for widening access applicants, so check you're eligible for that (https://www.ed.ac.uk/studying/undergraduate/applying/selection/widening-access) as if not you'll need the higher required grades.

You'll want the highest predicted grades you can get (to quote the Edinburgh website, "You must have achieved, or be predicted to achieve, our entry requirements for the degree you have applied for, to be considered for an offer of a place."). The A* in maths helps, but since unis mostly work in grades rather than UCAS points, it won't "cancel out" the C. Try and make a plan to show your teachers you can achieve at least an A in both of your other subjects before the UCAS deadline if you really want to apply for courses with this level of entry requirements. Of course, you'll want to pick your uni choices realistically, as if you get 5 unis offering AAB-A*AA and end up getting A*BC then you'll most likely end up in clearing, but having some aspirational choices is always good provided your predicted grades are close enough.

There doesn't seem to be a specific GCSE maths requirement for the course, so consider whether it's really worth jeopardising your other grades - your A level grades will be much much more important!