When you are paddle boarding, the SUP will be holding your weight against the water. That will cause you to float. When this equipment fails to hold the water pressure effectively, you will fall. Every manufacturer is aware of this fact. Thus, they make the SUP boards considering the weight of their potential clients. Buy a board whose carrying capacity is perfect for your weight.
Picking a board meant for a weightier person than you is not a good idea too. Although such boards will guarantee stability, they will reduce your speed and maneuverability. As a professional paddle boarder, you will be bored using such SUP. Pick a board that is perfect for your weight.