Most MBA programs, top 25 that is, "require" 4 years work experience. At least that's what they state in their admissions requirements. They will accept a few with no prior work experience. Get some work experience, at least 3 years, take a review course for the GMAT, Kaplan or Princeton Review and study your arse off. I can't stress that enough. Sad to say, but they use your GMAT score to weed out potential candidates.