It's common for youngsters to have PDD-NOS as a tentative diagnosis if they aren't clearly of the Kanner's make, and development will show which label fits them better.
I actually haven't been diagnosed with AS; I was offered to have the Autistic Disorder one changed to AS, but I declined. The psychiatrist who gave me the AD one knew far more about me outside of a professional setting than the psychologist I saw, who assumed that how I am with professionals is how I am with others (I'm aloof to others).
I know there's not too much difference between HFA and AS, but Kanner's fits my early developmental history perfectly, and it also fits how I am now, just of the "mild" to "moderate" make depending on where I am at the time. I like accuracy.
O, and to answer the question: 2007 at 25. Yes, quite late for HFA, but not unheard of.