no one can judge it. you decide what is your goal and how you want to get it. Being RN does not gurantee that you will get green card so soon. You might have to work with the hospital for 2-3 years..  which means..  3 years of your education and completing degree.. and then if visa available at that time then find yourself lucky. I am talking about Schedule A visas.
make a period of 5-6 years before you enter into med school.. and you spend another 4 years and then at least 2-3 years of residency. You decide what you want and how you want to get it.

On a side note, why dont you make some money and get out of this country and go home...   get into a medical school down there... gharmai basera masta sanga gharkai daal vaat tarkaari khayera mbbs saknu... ani ek dui barsh work experience liye pachi usmle garera yetai aaunu...   another 2-4 years of residency will help you to become MD here.. ..
just my personal thought.. good luck with whatever you decide.