dont buy your googles over the internet.
Go to a MX shop and bring your helmet to try different googles..nose shape can make a big difference in fit/confort

Personnaly i can't wear googles becuse of the shape of my nose, when i put googles they get squeeze between the helmet and the bump on my nose(nose bone) wich makes it very uncomfortable and push the helmet up, i have the same problem with my ski helmet. I always used sunglasses and in work perfect.