Experience is necessary but not sufficient to cause girls to envision a future career in computing. This study investigated the experiences and attitudes of girls who had taken three years of mandatory computer science classes in an all-girls setting in middle school, measured at the end of eighth grade. The one third of participants who were open to computing career were compared to the two thirds who were not. Girls open to a computing career had higher interest and confidence in computing, had more social support for computing, and saw themselves as more like a computer scientist than girls who did not want a computing career.