how much do AS grades matter?

hiya,

i did okay in my GCSEs (generally 7/8s) without trying very hard.
this year, i've hardly done any revision as i thought the same thing i did last year would work again, but it hasn't at all.
it's all my fault i've left things to the last minute, and i KNOW i am going to do terribly this year (C/Ds) as i know nothing.

i take biology, chemistry and psychology, and would like to do psychology at the university of birmingham.

i've read a lot of threads about how your year 12 'mock' grades don't really matter as you can persuade your teachers to increase your predicted grades.
however, my school pays for all a-level students to take the AS exams externally, meaning that our grades for this year will be official.

i'm incredibly worried as the grades will appear on ucas either way, so there's no way i could ask my teachers to increase my predicted grades. currently, my predicted grades are AAB, but i know for sure i'm going to get nowhere near those grades.

so, i was wondering, how much do official AS grades matter when applying for universities? will bad AS grades affect my chances for offers greatly? do i have any chance of getting in to UoB if i do badly this year, but really put in the work for year 13?

sorry about the very lengthy question, hahah.

thank you so much for any replies xxx

it will impact your predicted grades as your school with give you predicted grades and enter them into ucas when you apply to uni. AS grades is a good way for unis to gauge your skill after GCSE to see if you're settling in a-level propperly as some people just go down the hill after gcses, even the ones with A*S. In my opinion AS may give you an advantage compared to people who don't take AS and just do mocks at school.

I also do chemistry biology and psychology and have left things very late lmao like VERY late