Do I have to file a tax return?

21 year old college student, on a full athletic scholarship. My mother and father alternate every year to claim me on their taxes. During 2010, I was awarded my Pell Grant from both the 2008-09 and 2009-10 school year. I was also awarded my Pell Grant for the 2010-2011 school year in September of 2010. They totaled $12,801. During the summer of 2010, I worked camps at my college and was paid, with taxes being taken out of my paychecks. My mom,however, has claimed me on her taxes this year as a dependent. Am I required to file a return?