I was diagnosed with Aspergers at the age of six, but truth be told a diagnosis of HFA may not be too far off, as I did have somewhat of a language delay. I believe I started speaking when I was three, though apparently I didn't talk on a regular basis until I was four and a half, according to my parents. Whenever I did speak however, I would speak in full sentences. As well, it seems that around the time I turned six my vocabulary made an enormous leap, from being around the level of a 3-4 year old, to that of an average 12 year old. I believe this may have had something to do with dealing with the pressure of moving to a new town, and with attending Kindergarten (which I was enrolled in twice; I'm not exactly sure when I started my first year, but I finished my second year when I was 6).
As for an NT diagnosis, while I have adopted some more NT-ish mannerisms and behaviors over the years, mainly just as a way of adapting to the NT world, the fact remains that I am most definitely on the ASD spectrum, and that anyone who claims that I am not has no idea what the hell they are talking about. My sensory sensitivities alone pretty much scream ASD, never mind my behavioral differences, my literal thought processes, my obsessive interests, and of course my emotional differences.