There are plenty of geniuses out there with like 5A*s at A Level and still don't get into medical school. At the end of the day, academics is just part of your application. Your personal statement and interview are also incredibly important if you want to get in so I would say AAA is completely fine. You may want to avoid Oxford, Cambridge, Edinburgh and possibly Imperial however but with a strong UKCAT score you stand just as good a chance as anyone else. Have a look at the applicant profile pinned to the top of the forum and you can see people with your predicted grades getting into medical schools.