A friend who is in the Air Force told me it normally takes 5 years from the time a guy enlists to the time he is a functional and operational PJ. Is that true?

Nope, from the time you get to basic to the time you are operational is about 2.5 years. Which is when you get to your first unit and complete your mission qual training. There are lots of people who have deployed within months of getting to their first duty station.