I am currently on an EB2 E26 category on which I received on March 2012 from my previous employer in GA. I entered under the same sponsor as H1B category in May 2010 and was adjusted to green card in March 2012 with no problems encountered. I am a physical therapist. However, after 3 months, I quit my employer and moved in here to CA. I am still working as a PT here but on a home health setting and is an independent contractor and is no longer connected to my employer who sponsored my EB2. I also informed/updated USCIS of my new location. My questions are: 1) When can I possibly apply for US Citizenship? and 2) Will I encounter problems when I apply for US citizenship? Thanks.
Typically you can apply in 5 years from your approval date. Also it would depend on the officer and they may ask you why you decide to leave the employer soon. You could also talk to a good lawyer who can completely review your case and provide proper guidance.