Financial questions that need an answer

I am only 20 and I have old w2 forms going back to 4 years ago. I never file for taxes and now I am and i was wondering if I could file old w2 forms. On all of the forms the government owes me money and I was wondering if any websites supported filing old forms. I also prefabricated over 3k this year in taxable earnings and heard that if I file I get an extra 600 dollars from the government, is this true?