Alright, comparing yourself to other people again. It seems to be all life is, doesn't it? Life is selling yourself for scholarships, college, jobs, everything. But that's just it. Life is selling YOURSELF. You need to tell everyone what YOU are good at. Not what you are bad at, not what you wish you were, but what you ARE, what you're good at, what you can do that no one else can do as good as you.
Yeah, to some extent you want to live up to expectations, you want to exceed them. But in some ways, exceeding those expectations is failing in one thing and totally excelling in another thing no one expected.
Don't feel worthless. You can improve, and let me tell you that the feeling of worthlessness is the most common reason that people do not improve. They feel that they cannot do anything valuable, so they make no effort to do anything. Don't let that be you. Anyone can be someone worthwhile, someone to make a difference, but it calls for a lot of hard work and continued improvement. A good way to improve is not believing that it is impossible to improve.
Maybe you can't do as well in school because of your condition, and that is okay. (Just be sure you aren't finding a scapegoat and calling it ADHD, I don't know much about it... think it's an attention disorder, which could make sense) But no one else is you. Find something you are passionate about and go for it. And try to aim higher than working in a cheesecake factory ;)

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