First, since girls aren't supposed to be into computers, they aren't exposed to computer science when they're young, and even if they are, they often aren't encouraged to pursue their interests in the field. That helps explain why only 22 percent of the high school students who take the AP computer science exam today are girls. Kayla didn't know she wanted to be a computer scientist until she'd already started a totally different career, in library science. It was only when she started training staff to use the library's software that she realized she might be interested in making software herself, so she went back to college for a second time to be a computer scientist. Kimberly had never heard of computer science until she saw it was one of the classes she could take at her local community college.