Pretty much selftaught, but I actually learned very much from art-lessons and books, because they offer more effective and simpler methods of drawing than I'd ever find out by myself.
It is a much easier way to learn, because: why should I find it all out by myself when there are plenty of good teachers whom experience and methods I can benefit from?
Plus, if you learn all by yourself (through trial & error for example), you can get stuck very easily so either you stick with what you call your "style" (which is actually only a matter of inexperience or a lack of openness to new possibilitys) or never get the "clue" or see mistakes which other people from the outside would see (friends normally only say "it's pretty good!" instead of giving advices unless they are artists themself).

It's true that most artists today believe that art should be self thought and I pretty much agree with that because everyone has his/her individual access to art and needs different methods. But you shouldn't avoid art lessons, especially if not very experienced yet - they can teach you things invaluable and which can boost your artistical skills and give you more freedom of choosing the methods that work for ya!