I want to become a crime scene investigator. I want to obtain my associates in it what do I need to study and how long does it take?

Well what do you want to do, gather the evidence in the field, work in a lab, work as a evidence clerk.

Most of the people doing the lab tests will have very advanced degrees in that field. The ones collecting the evidece, Photo, putting it in bags and so on, normally a college degree ill do.

Please understand, most places do not do it like TV, they don't go from the lab to the field and gather the evidence then take it back to the lab.
Most crime lab people never leave the lab, but just go though the evidence sent to them by the police, by other departments,or by crime scene techs who collect the evidence.