I had a similar experience as Neutropeniaboy - mine was regarding board scores.
Was at a top program, too, and was asked by the Chair - "So, you don't have at least a 250 on your Step I, so why should we accept you?" Can't remember what I said, but was put off a little.
If it isn't AOA, it'll be board scores, research, publications, personality or a variety of other factors that they'll focus on.
Just do the best you can, be humble in the interviews, remember that everyone you come into contact has a say in the rankings, try to relax - and you should do fine.