I'm not a believer in CJ degrees. I have some buddies who did that, and they regret it. Get a degree that you can use if you need to: business, economics and even "liberal arts," since that covers a lot of ground. Remember, when an agency requires a college degree, it doesn't matter what it's in, as long as it's from an accredited college/university.
What does it take? Check out your local department, look at their requirements and apply. I was 6+ years into a completely unrelated career when I did that. The process took me several months, but it was nothing painful. Be prepared to provide a lot of references that aren't family members, or related to each other. Be prepared to list a lot of background information, such as every job you've had for the past 10 years or since you were 18, all the places you've lived, etc.... That was the toughest part for me, since I was in my late 20s.