2 centimeters isn't going to make a big difference. a smaller board will be easier to maneuver, while a longer board will be more stable at higher speeds. a lot of snowboarders have different sized boards for different types of riding, you're not going to want to take a long board to the park. Just be sure that you're foot will fit on the board. a good website to help pick out boards is Snowboard Reviews | The Good RideThe Good Ride
you can narrow down the boards by selecting different options.