Can I start taking classes for RN to BSN program even before im an RN??

I don't see why not ! I'm in the LPN program, and before I got in the LPN program I already started classes for my RN BSN program. I have a few more to take before I apply though.

Look into your school’s requirements. Most generally the nursing courses build upon one another so I doubt you would be able to start any of those courses prior to finishing your associate’s degree. Also, one of the entrance requirements for the RN to BSN program is that the student t must already have an uncumbersome RN license. If you are looking at taking general education courses to fulfill other BS degree requirements, then I don’t see that being a problem. The only thing I would caution you on is if you are depending upon financial aid to cover your costs, you may run into a snag. In order to receive financial aid, the student must be a degree seeking student. If you are unable to meet the entrance requirements for the RN to BSN program, you will more than likely need to pay for those courses out of pocket unless the school you are currently attending for you RN has an agreement in place with the school you are looking to attend for your RN to BSN.