NSF GRFP if I already have a MS

<p>I received a BS and MS after 4 years of college (I took a lot of grad classes, wrote a thesis, and published). I wouldn't consider those 4 years to have contained any "full-time" graduate work, but here's my question:</p>

<p>I'm planning on applying to a Ph.D. program (biology) this winter. Am I eligible for the NSF GRFP? I don't know much about the fellowship. I actually just found out about it quite recently.</p>