When choosing a SUP for surfing, it is important to consider the size of the waves you will be riding. If you are going to be riding small waves, you will need a smaller board. If you are going to be riding big waves, you will need a bigger board.
Additionally, it is important to consider your height and weight when choosing a SUP. Generally speaking, taller and heavier riders will need a bigger board, while shorter and lighter riders will need a smaller board.