The DSM-IV 299.80 definition for Asperger's includes an absense of delayed speech development. If your speech development was substantially delayed then an AS diagnosis would be unlikely.
The doctor is probably more concerned with whether or not you meet the criteria of section 299.00{B} for an autism diagnosis. I assume she wanted to find out whether your motorcycle motions meant you were pretending to ride a motorcycle (which is imaginative or symbolic play) or if you were merely engaged in a repetitive motion. Assuming you met all of the other conditions for an autism diagnosis, then the absense of imaginative play would be a fast-track to that diagnosis. If your play was in fact imaginative, then the doctor would have to evaluate your speech and socialization capabilities at that age, which (as you've noted) is difficult if your parents can't remember your development milestones.
At first glance, it would look like the decision is between autism and PDD-NOS, not autism and AS.
Then again, I'm not a doctor....
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