I think pharmacy is a good choice to be honest. I recommend a few things though, why not pick up the phone and call other universities such as London school of pharmacy or whatever and explain your situation. With 3 As they might be willing to make space for you on their course. My cousin got onto a medicine course by calling different universities on results day, at first everyone university told him they didn't have places, he went to Liverpool university (the nearest one that does medicine) looked for the head of medicine and pleaded his case, two weeks along the line a place pops up and now he's just finishing off his fourth year.
All I am saying is even if you do accept the course at aston as a firm, you can still call other universities and plead your case, you may got on a pharmacy course at a better uni or you might even get on a medicine course.