I would consider myself a "Doodlist" over a Caroonist. My high school, college, and church bulletins are filled with random graphics. Though I made a D in junior high art it did not keep me from succeeding in high school art. Though my high school drafting teacher told me I'd never make it as an Architect I am now a licensed Landscape Architect and the owner of Cumberland Landesign..
Have focus, drive, and tenacity and you will succeed.
Remember, if someone says you can't do it, then it's just that they can't do it.