Since Spinelli's Stargirl is written from Leo's perspective, readers see Stargirl from the narrator's point of view. For example, many of the students, including Leo, do not believe that Stargirl is authentic. Hillari tells everyone, "She's not real," but they are in for a surprise because she turns out to be the only "real" person at Mica Area High School (7).
Some of Stargirl's character traits that the students witness are her friendliness, kindness, and originality. She is friendly because she sings to others in the lunchroom on their birthdays. She is kind because she not only cheers for the high school's team, but for the opposing team as well; more importantly, her originality shines because of the way she dresses; she does not act like other teenagers—at least not at first. When she does try to conform in order to keep her relationship with Leo intact, she discovers that she cannot be happy acting like anyone other than her true self.
A few other characteristics to include with the above might be that she loves animals and that she is not prejudiced in this regard because she has a pet rat. (Something most girls would not even touch!) She is also naive to vanity or pettiness. For instance, when the whole school is mad at her in chapter 25, not only is she clueless to that fact until Leo tells her, she also does not understand why people are so upset. Leo tells her something has to change and she thinks she has to change a bike tire! She is very childlike.