You are young. Stop putting yourself down. Ask yourself, have you really tried your best? Given your all?
Set some concrete goals. Find something you're really interested in, or something you can cope with, and then focus on getting really good in that. That means never giving up in the face of failure (but always learning from your mistakes), and most of all, believing that you're going to become awesome at what you do.
It's the nature of my circuitry.