He considered her the weird girl and she saw him as a boy eager to fit in. When Cory ruined his hair in an attempt to straighten it, she was the only one at school who didn't laugh at him at least not initially. Topanga, and the other outcasts at school were trying to get a petition signed to save the job of one of the teachers and it's Cory's crazy, bold idea that manages to get some attention. The outcasts handcuff themselves to lockers, blocking the hall and after a speech from Cory, the kids go sign the petition. This impresses Topanga and she thanks him by giving him his first kiss, though he's not as receptive to it since he's still immature and more interested in sports than in girls.