The mass of skater affects the magnitude of the kinetic and potential energy.
Kinetic energy can be said to be the energy which an object posseses due to motion while potential energy can be said to be the energy stored in an object deu to the position of the object relative to other objects.
The kinetic energy of the skaterboard is based on the mass and velocity of the board. The speed of the board changes while the mass remains the same. Thus, we can say the kinetic energy changes.
The potential energy of the skaterboard is based on the mass of the board, height, and acceleration due to gravity. As the skaterboard moves, the Kinetic energy is converted to potential energy