Ya know, from what I remember from school don't they tell you what kind of thing you need to draw/paint instead of what you are best at? idk, just a thought. You may not have high praise about your artwork then, but that doesn't mean that you're not good at it.

Don't quit because somebody told you that you weren't any good at it. Einstein failed math I think and look at him now...the amazing things he's invented that includes mathematic formulations. If you look at the history of the famous painters, inventers, singers, etc. you'll find that many of them actually flunked out or were told they were the worst in the fields that they became famous for! What I'm saying is that don't give up the dream that you've had for so long just because somebody said you couldn't do it.

You have my faith that you can succeed!