Where to start

I may be here under false pretences but recently I have begun to wonder, at the ripe age of 57, if I might have Asperger's.  So many things seem to fit, difficulty in social situations (popular in the work quiz team because of my ability to remember odd facts though), forensic interest in unusual subjects etc.  I'm worried I might just be trying to force a square peg in a round hole to explain generalised social ineptitude. 

How do I get confirmation one way or the other?  I can't imagine plumping myself in front of my GP and announcing 'I think I have Asperger's, please test me'.  This is assuming I could even get an appointment.

Can someone help me start on this path?

Many thanks