Millions of federal student loan borrowers who graduated in the spring will need to start repaying their debt for the first time soon . That's because the six-month grace period that the Department of Education allows students after they finish school is winding down for May graduates. "In other words, 'Happy Thanksgiving!'" said higher education expert Mark Kantrowitz. "It's time to start making payments on your student loans." Outstanding federal education debt in the U.S. exceeds $1.6