If you're in it for the money, you're in it for the wrong reason
^^ This man's advice is spot on.
As for OP @Tb:) :
If the military isn't for you, go to school. But don't major in something like criminal justice or criminology. If for some reason you end up in a wheel chair or things don't work out, those degrees are super specific. Find a happy medium. Don't major in some liberal art, but maybe something like accounting, or public admin. etc
Look at local departments, see if they offer a cadet program. Some of them are paid and offer 20-30 hrs a week working a desk in the precinct or evidence/permit distribution. It's a great way to get your foot in the door.
Also look to see if your department offers civilian ride alongs. Go see what the job is really like, ask questions. It's not something you want to go into blindly.
Also. I would hold off on the academy unless you're sure you have a job lined up. It can get expensive and some departments will sponsor you and pay for you to go through the academy.