The suggestion above that "the more A levels the better" is incorrect. You only need three A levels, and taking more than three may damage your chances of doing well.
OP, if your predicted grades at the end of year 12 are BDD, you won't be a competitive candidate for Oxbridge or other Russell Group universities. Your best bet would be to work hard in Year 13 and then apply to universities with your achieved grades. Bear in mind that would need to achieve AAA to have a chance of a place at Oxford, and you would also need to do well in any subject-relevant aptitude test and at interview, if invited to interview.
It is good to aspire, but aspirations should be realistic. Try not to fixate on any one university.