From what I could find...
And there are many others but if you check around you can see that anyone doing anything in anime today was largely self taught. Most people only go to school to learn the theory and get a degree or certification. Having a degree makes you more likely to get a job in certain industries. (I suppose)
Truth be told, most of them went to art school but before you jump to assumptions, have you ever heard the term in college, 'you read for your degree'. If you haven't it means that simply going to school isn't enough, you have to go the extra mile and do the work. Artists like Akira Toriyama and Kishimoto were drawing years before that. Granted that might make you feel dismayed when starting but with determination anyone can do it. Like all skills, natural or not, they have to be nurtured.
..You have to be confident to draw..
As it relates to everything, not just art and anime, we as humans like to base what we want to do on the success of others but that can only get you so far when starting out. Just try something for yourself, its nice to have influences but If you plan to take it seriously you will have to be original amongst other things. I leave you with this comic.