Hi Skimbleshanks
Depending on your age there's a possibility you could have had autism all your life but be high functioning and therefore it wasn't diagnosed earlier. There are many different levels and types of autism. It's only in the last few decades since sufficient research and testing has been done that diagnosis has become more readily available. Anyone who was a child in the 1960's, 70's or 80's, who may have mild to moderate autism or asperger's, might have been put in a standard school system and learnt to cope and never been diagnosed.

Has the neurologist suggested further testing for autism? Did she give any indication of what type she thought you might have? I have not heard of anyone developing autism as an adult (that's not to say it's not possible) but you say your onset started about 3 yrs ago - this would suggest an acqired disease or reaction to something. Also the question about exposure to heavy metals may be in relation to Neurotoxicity, depending on what condition the doctor was trying to diagnose.

Sorry this probably leaves you with more questions than answers. Are you due to see the Neurologist again? Did you get a written report from the neuro appt. - if not - requesting a copy might give you more info. Maybe you could ask for specifc answers next time she asks such vague questions. Don't be anxious about the doctor asking you the autism question - if she didn't give you a definitive diagnosis then she is just considering any and all possibilities.
All the best in your search for answers.