Believing in yourself is essential, yet your vulnerability can be destroyed in an instant. You must know someone whose friend, boss or teacher said the wrong thing and crushed them, making them have self-doubt for years. Self-confidence is more than just a human quality, it is at the core of what we do.
I was asked if I would change anything I had done in my life, given the chance. I said no. If I had changed anything I did in the past, I would have changed who I am today. I have my faults, but I like myself and still have the confidence to believe I can do almost anything I put my mind to.
Love who you are, be positive about who and what you can still become, and believe you can accomplish almost anything you genuinely have a desire to do.