That's a big question if you're an adult. Wondering how long and why you think this to be so?

Have you thought of contacting an adult support group in your area for advice? e.g. http://www.autastics.org/ There are other groups as well.

Here is a little more information from someone I trust very much. Tony Attwood - What is Asperger's

http://psychcentral.com/lib/2011/adu...f-a-diagnosis/
Adult Asperger’s: The Relief of A Diagnosis
By Marie Hartwell-Walker, Ed.D.

p.s.
There are also some links in Useful Sites which is at the top of the threads on this page.