I am a Corrections officer with seven years in.
I have 60 college credit hours in criminal justice.I want to be in PSU.Can I go REBI with my back ground or do I have to be a police officer?Is PSU considered federel law enforcement?Is it an elite tactical unit?

PSU is NOT a tactical elite unit. It is a deployable Force Protection Unit. It is not a Federal Law Enforcement unit as we don't do much of the standard boardings etc.

Speak to a recruiter. Since there are security guards being allowed to use their work as a means to go to REBI , I don't see why you wouldn't qualify as you are part of the criminal justice system.

Ad BTDT said, we've seen people with a lot less come in as a PS3.
If you've been through a formal corrections academy that should be enough.
Go to a recruiter that knows the reserve programs and say you want to be a PS3 through the RX program and tell them you are a local/state/federal CO, have been through an academy, have college credits, have experience, and want to be in a PSU (for most a critical billet that needs fresh faces).
I think that shoudl make them smile and be happy they have a good candidate.