Actually, their not points, their centimeters. It's the length of the board.
The proper length is determined by your weight as well as your riding style. What I would suggest is start by doing a online search for snowboard length calculators. Go talk to a few shops, fellow riders as well as instructors and see what they suggest. From there determine what style of riding you want to progress to. If you want to get into riding the park, stereotypically you'll want to run a shorter board, commonly called a freestyle
board. Their usually easier to spin, etc.
If you just want to do all mountain, then an All mountain
board may be your choice. the added length helps in stability at higher speed, but still short enough to play in the park if you should so choose. As a beginner, I'd lean to this type of board. Their usually more of a do-it-all type of board.
If you want more info, I'd suggest spending some time online doing research. Here's a pretty decent site to start with. http://http://www.cju.com/snowboard/...D98B94794.html