Most answers in this post are full of engineering fail. What exactly are you arguing? Yes she is right...more mass = higher Vmax. Assuming two objects have equal Cd and frontal area in the same atmosphere. Terminal Velocity occurs when D = W = m*g, drag and weight. Drag equation => D= .5*rho*V^2*Cd*A Then you can calculate Vmax. You can see a larger mass object will have a higher Vmax assuming everything else is constant.