This is going to depend on a variety of factors, as the posts above have pointed out.
If we are only talking about art class then the teacher, curriculum, classroom standards and the types of art created in class will be the determining factors of difficulty.
However, we can all find a mode of art that suits us if we look around for a while. You don't need drawing skills or painting skills to make sculpture and the same is true in the opposite direction. Collage, craft, and fabric art all call for different skills which you may have in you, waiting to be developed.