What sport should I take to have a better looking body?

[moo?]

Im a 15 year old freshman girl in high school and am 5'7" and my body is beginning to become less curvy and i have a tummy now due to my new poor eating habits caused by to much stress with school (im guessing that's a big cause of it). Im interested in taking a sport next year and I was wonder which one I should take to have a flat stomach and better body and a overall skinny looking figure. Im interested in taking Tennis, Track or maybe swimming (im not sure on swimming, I did it for 5 years but as i got older they started to work me to the bone and I started to have trouble breathing after 20 laps of no rest X.X ). I don't know which sport would be best but I don't want to have so much muscle were it becomes un attractive. Im interested in becoming a future model and am hoping i will grow taller (moms 5'9" older sister is 5'11"). I don't want to be one of those anorexic ones I want to be healthy and be skinny in a healthy way.