She is mostly invulnerable to damage, and possesses potent magical abilities. This allows her to retain her youth and beauty. She also possesses the "Wisdom of the Owl" which grants her a form of enhanced intellect, presumably heightening her memory and ability to process information.
Due to her invulnerability and powerful magic, she remains young and attractive. Her "Wisdom of the Owl" provides her with heightened intellect, likely improving her memory and ability to process information.