No worries about your weight, the more you ride the more excercise you will be getting :)As for board size, remember WIDTH is the most important factor. Use a board that gives you enough toe and heel hang for good leverage, but not too much that it would drag in the snow. My rule is 1/4 to 1/2 inch boot hang on both heel and toe side. As for snowboard length, a longer board will help you GO straighter and faster, a shorter board will help you TURN faster and be more manuverable. Ride On,Frosty