3 years in A level and a Uni offer?

Hi
I got 7 As and 5 Bs in my GCSEs.
At A level in year 13 I am doing Chem, Bio and Maths. I am taking a gap year. I did not apply to uni because my AS grades didn't meet the criteria for the course I wanted to do-Biochemistry and I just thought (wasn't fully aware-didn't even know what a foundation year was about) the universities wouldn't even want to look at my application.
I have given some of my AS retakes this year and I am now going to be doing A2 exams from this week. I feel that my exams won't go well this year because I mainly focussed on my AS retakes (which were about 5).
I was wondering if I retake my A2 exams in 2017 then will universities accept me on the basis of my A2 results for 'A deferred entry for 2018' (I am thinking to apply for the deffered entry in 2016)? And if I get the grades in 2017 then will I be able to join uni from September 2017 instead of 2018?
I really want to go to university. I just don't know what to do.
Thanks

When you defer you still have to meet those grades by the end of august that year,not your year of entry for the most part. Also, you can't always undefer too easily so why not try for 2017 entry anyway.

I am definitely going to try but I just feel like my exam results are going to be a disappointment. How about applying through foundation year? What are the usual grade requirements for that?