HELP

Hi, I've just finished school without applying to university without any idea what I want to do. My GCSE's were fine with 2A*s and 9As, but my AS levels went awfully (BCDD in Drama, Politics, Philosophy and Biology). I dropped Biology as it was the hardest to resist and continued with the bother three which were actually three subjects that I completely hated coming into A2s. I had no motivation last year due to boredom with my subjects did not try at all and was basically going nowhere, I'm yet to get results, but I can't imagine them going well. I have never revised for an exam, only the night before fire to complete boredom with the subjects. However, I feel as though I've had a bit of a 'revelation'. I want to do medicine and I want to do surgery. I know this may seem fickle and stupid, but this is the one thing I've come across with is actually motivating me, I can't quite describe it. My question is, if going back to college to gain A levels in the necessary subjects (Chemistry, Biology etc.) will medical schools look down on me? I know a lot of medical schools don't like resits, but this isn't really resitting rather than rechoosing. I know I took biology at AS, but I didn't have any intention of doing anything with it then, despite it actually being the one subject I enjoyed. Will I still be able to go to good medical schools as a mature student (probably starting age 21) with reformed A levels, or is this not an option?