The scary thing about self-development is the thought that you're becoming more yourself. While in reality you're moving away from who you are and use your lack of self-acceptance to justify becoming who you want to be. Which at the current time of that thought, you're simply not. It's scary to believe in a lie. It's good to move to a better version of yourself. Instead of this lie I would like you to at the very least acknowledge your flaws and decide firmly to develop parts of yourself in order to become more prosperous, whole and happy. This way you still validate yourself but see your flaws for what they are, simply flaws, because you were never a bad person to begin with.