Whereabouts in Canada are you? I'm in BC.
It really depends on the GP. If you happen to have a doctor that has actually read about Asperger's and has known some people with it, you will be in good luck. Otherwise, you have to be prepared for the doctor to tell you outright "no you're not like those people" due to the widespread stereotypes and lack of education in that area for the average GP. It would be a good idea to take an article or checklist of AS symptoms and then on another paper list the reasons why you match those symptoms. My first time when I mentioned that to a doctor he thought it was ridiculous because he said "I met an Asperger's guy, he sounded like a robot, you don't sound like a robot, I'm really sure you can't have Asperger's." (Even though I actualy do sound "Aspie" often because I wil rant on in a somewhat monotone voice, at least for a girl.) And he wouldnt give me a referal to a psychiatrist to check it out
Two years later, a couple months ago, when I was seeing a psychiatrist for other issues, I mentioned a few people with experience thought it was likely I had Asperger's, and he laughed out loud at me! He said basically "I've seen autistic people, you don't act autistic, those people must be wrong." (rainman?) Then when he was talking with my mom on the phone, my mom gave him lots of real info on AS (she worked with some AS kids and thinks I have it) and he admitted he hadnt actually read anything about it beyond the DSM-IV. After that he appologized and asked me some real questions.
So, its normal to be nervous, but its important to really prepare yourself for ignorance. Just realize that it's common for people not to know much about AS, and if they tell you you can't have it, ask for a detailed reason why they disagree with your symptoms. If they can't adequately discuss common symptoms of AS, you can probably tell the doctor is not well informed.
But don't take it personally! Of course its possible you dont have AS, but you want at least the opportunity to properly discuss it with someone who is experienced and knowledgable before you accept the "no".