Six pack for a teenage girl?

Hey! Well, I have really wanted a six pack for a long time, and I'm wondering how to get one! I just turned 14, and I'm a girl. I play traveling soccer 4 times a week, where we do a ton of sprinting. I also go to the track some mornings, about twice or three times a week, and run a mile. Do crunches/sit ups help? I have no idea how to actually form the muscles. And how long would it take? Please help!! Thank you.