You can't just go off of height and weight. If I didn't constantly cut weight, I would be over 200 pounds but I stay around 170 and I'll cut back down to 170 when I hit 180. But 5'8 155 is not small in my opinion especially if you're in your early 20's or you're keeping your body fat % low. I'm 5'10 and would prefer to stay around 160 if I could help it. Just me but I would rather be ripped, strong and agile rather than bulky. I don't know about the board but I see plenty of ball players around your size.