Do I have asperger's or am I extremely shy? How does one differentiate the two?

Aspergers. Shyness does not equate asperger's. But a licensed psychologist can help you figure out which is which. Here is a video overview. http://www.youtube.com/watch?v=xg1ngp1ngds.
Probably "shy" Most people with asperger's aren't shy. They have great difficulty in social situations which can lead to anxiety in social situations. Extreme "shyness" can be a symptom of social phobia which is a treatable disorder. I would recommend seeing a psychiatrist who ca help you with the distinction.