Welcome to FT JCookery!!!!!
Sorry, but I'm not sure about the visa.
My parents went to Turkey for 3+ weeks in October of 2001. Several people in their group cancelled (post-9/11 fear of flying, etc.). They travel a lot and have said that it was their best trip ever. They plan on going back next summer.
If your trip is more than a month from now, I would still go.