If you look at Oxford and Cambridge college applications feedback pages, you’ll see the typical GCSEs of those who apply and who get to interview and who get offers. In all cases, the averages are higher than the OP has by a big margin. This doesn’t mean they can’t apply or that an exceptional candidate who has a good and clear reason why their grades at GCSE were lower than you’d expect and than their talent suggests, the vast vast majority won’t get far with such grades.
Oxbridge want super students to apply. Super students usually have top top GCSEs. Occasionally they don’t and they want to be able to consider them too. But you have to be realistic and know that unless you had a very specific context going on that explains why your grades are not impressive across the board, others will mostly have all 8s and 9s. Take advice from your school or college. Know it’s not just about being keen but you need to be top and top in your school and that many people who are top and top in their school still don’t get offers. You’d be surprised how many candidates there are out there who have all 9# or 8/9 at GCSE.