One thing I wish I would have internalized earlier in my life is that who you are as a person is not set in stone. Your strengths and weaknesses, emotional and physical states of being, even how you view yourself... these are all malleable. This is good news. It means you can become whoever you'd like to be.
It's a fine line between self-improvement and self-loathing. It's entirely possible to love who you are while you are improving yourself. The key to this, from my own trial and error, is accepting that nothing exists in a perfect state (including yourself). It's therefore neither offensive nor pessimistic to assume your own person could be better at every moment of life. This is actually a freeing realization. You never have to be perfect, because it's not possible for you to be perfect. All that matters is that you are trending in the right direction.