One of the common questions people ask an illustrator or a graphic designer is that if it is needed that they know how to draw to become like them. That is because there is an image that should be produced. One illustrator has shared her experience. When she was young she began to draw anything that she can think to draw. She will trace her hands if she does not know what to draw and then color it. As she grows up, she just continually draw anything.
Even if there are obvious improvements as she draws but there is something lacking in them in her feelings. She just persisted and continue to draw as she grows up. She enrolled in classes so she can improve in her drawings and that she could have a deeper understanding about what is she doing. Now she became an illustrator. She learned how to use the programs so she could also draw the things in her mind. What she can say in the drawing is that you can learn it.
Even if you do not have the ability as they say if you keep on practicing then you can be able to learn. If you can learn in art school then do so. It will help you if you want to pursue a professional career using your drawing skills. But knowing to draw is not the only thing that you will need to be an illustrator or a graphic artist so take time to learn and practice always.