If a CRO wants to go on a mission, Do they need to ask for permission?

I was looking forward to being a PJ but then I found out they were enlisted. I've heard about CRO's. They are like PJs exept they don't go on as many missions. If I am a CRO and I really want to go on a mission, Can i go? After all I would be an officer. If I can't make CRO then I will try STO. and if that doesn't work i will do USAF Security forces. Is there an officer version of security forces or is it co-op?