Yeah, my story was similar. I was at an academic girls' private school that didn't even pretend not to care about league tables. I was primed for the Oxbridge stream from the middle of secondary school at least, I was confused about what subjects I wanted to do for A Level and hated having to drop any of them, and I had some absolutely outstanding teaching for the A Levels I did take (maths, chem, biology and French). I picked Oxford over Cambridge because I wanted to get away from home, and because I was pretty confident by then I wanted to study biochemistry rather than general natural sciences.