I love that the Supergirl's quote is 'Believe in Yourself'. That just strikes home for the character. She is someone who has developed into her own person, handled the difficulties that life has thrown her, and become the hero she is.
And the fact that she seems so comfortable in her skin, playing with Streaky, happy, and joyful and smiling as she is flying. I love this. And if you want to see more, you should definitely hit that link.