In this story, Connie transforms from a girl who seeks to validate her own superficial ideas to one who is willing to sacrifice herself for her family.
As the story opens, Connie bases her self-worth on her looks: "She knew she was pretty and that was everything." She endures comments from her mother, convinced that the scorn she receives is because her mother has lost her own good looks and thus feels the need to belittle Connie's. Connie is deceptive in order to obtain what she desires—some unchaperoned time with boys. She acts as part of a collective, making decisions with the group of girls who sneak circumvent their parents' rules with her:
One night in midsummer they ran across, breathless with daring, and right away someone leaned out a car window and invited them over, but it was just a boy from high school they didn't like. It made them feel good to be able to ignore him.
They didn't like the boy and thus they ignore him. Connie seems incapable of independent thought.
This changes when Arnold Friend appears at Connie's house. At first, she is simply dismissive, not even seeing him as a threat, which is true to her character thus far. In fact, her first thought as the car comes up the drive is "how bad she looked." As Arnold emerges from the car and engages Connie in conversation, she is true to her initial character:
Connie blushed a little, because the glasses made it impossible for her to see just what this boy was looking at. She couldn't decide if she liked him or if he was just a jerk, and so she dawdled in the doorway and wouldn't come down or go back inside.
Eventually, Connie realizes that she has made a mistake and that Arnold actually poses a danger to her. She asks him to leave and threatens to call the police, and Arnold then vows that he will take revenge on her family if she does:
But if you don't come out we're gonna wait till your people come home and then they're all going to get it.
Arnold Friend seems to know everything about Connie and everything about everyone she knows. She thus begins to believe his words and slowly realizes that she must sacrifice herself in order to save her family. This is an independent act that the Connie early in the story could not have fathomed. As she leaves with him, Arnold assures her:
You're better than them because not a one of them would have done this for you.
Thus, Connie proves a dynamic character who in the end values the lives of her family more than her own and leaves with Arnold Friend to meet a certain and violent death—and her family will likely never know of her sacrifice. Connie's final act is independently selfless, a sharp contrast to her shallow beginnings in the story.