Scott,
From your description of yourself and your mechanical abilities, you are well prepared to build your aircraft. I can relate to your activities with cars as I had previously built and painted several street rods and done I don't know how many engines. Aircraft technology is pure mechanics, physics and techniques just as building cars is and I think you will find transitioning to be a natural activity with a lot of interesting new things to learn (like how aircraft hardware is sized and why weight is important)
In the time waiting for my kit I found perusing the aircraft spruce catalog to be an interesting and motivating activity just for the sake of understanding aircraft materials and hardware. Also spent some time helping out an A & P with restoring an old short wing piper.
Another great point about choosing a Kitfox. I recall one of my EAA tech counselors raving about how complete the Kitfox build manual was - way better than most.
So 'ya did good!
Sincerely,
Dave