What you think of your self will eventually be who you are.
We create our own image of ourselves, look in the mirror who do you see ? I heard a saying once “fake it till you make it”.
It doesn’t mean to lie. It means believe in yourself or nobody will believe in you. Success and Failure spreads like a virus, the good news is we create both. That means we can to some degree control our destiney. Everyone fails, there isn’t a person alive that hasn’t failed at some point in their life. I know of another good saying “winners never quit and quitters never win”.