I was a freshman this last year at D2 Northern State and the biggest thing I noticed when I was on the mound was the speed of the game.
Runners are faster
Ground balls are harder
Fly balls are hit farther
Everyone throws harder
Just stuff like that. You don
t have all sorts of time during a play. Also, coaches dont tollerate as much. They expect you to know the signs at all times, score, number of outs, situation, ect. Just mental stuff all has to be engrained in your head.
College baseball is soooo much fun and you will not regret working hard to get there.