Hi,
I'm a natal female but have a very large, masculine jaw and am scheduled for surgery with Dr. Bart in August. So I don't think it's a problem at all if you're not actually trans (lucky for me!).
The waiting time for my consultation in Ghent was not long at all - 2-3 weeks at the most I think. He told me that surgery appointments usually need to be booked about 3 months in advance (a little more if you want to have surgery in the summer months, which are apparently very popular).