Explain Leo’s intentional description of star girl having “no ego”. What does he mean by that and give examples of her behavior demonstrating it.

Stargirl doesn't seem to be like most of us. Most people validate themselves through the ego. People crave people and things to make themselves feel valued. Stargirl doesn't need to be validated by circumstances, people, material possessions. The very fact that nothing and no one and no circumstantial situation is enough to convince Stargirl to accept the impositions upon her cultivated outsider status the shackles of societal conventions is enough to situate her as something more than a mere case of weirdly non-conforming character. She is steadfast in her conviction that one should remain true to themselves even—maybe even especially—at the cost of losing the friendship or respect of others.