1999 Subaru Outback First to second gear

Engine Mechanical problem
1999 Subaru Outback All Wheel Drive

When I am changing gears from first to second, it often seems that the shift comes out of first gear too easily. It never comes out of gear on it's own, you can just tell that it slides out of first gear a little too easily in comparison to all the other gears. What kind of problem does this sound like? I am guessing clutch, or worse yet transmission, but I don't know.