If you already have a degree why not look into the FBI now, also you have to look at what it will do to your new family, will she stay by your side and be willing to become a "military wife" or is she expecting more?
It sounds like you yourself has some doubts too that does not make for a good enlistment,
As for as enlisted in the airforce I would say your best bet would be PJ or into Security Forces then get into a Specialty like a raven or OSI investigator.
Ive been in 20 years in Feb but I Do have the support of my wife and it has made all the difference in the world when that phone rings for a mission, I was very serious with someone before who used to argue over that, It's very hard on them and in turn they can make it hard on you, you don't want personal problems interfereing with your decisions on the battle/training grounds. you might make 20 but as a boozer who never made command level. Think long and hard about the choices ahead of you. It will affect the rest of your life, Mine has been great and I would do it all over again but.. I also have a very understanding and caring wife and children.