How to get my parents to stop making me do swimming lessons?

Im 13 and I've been doing swimming lessons since I was 6. Every like 10 months I move up a group. I'm two groups away from completing everything but I think I'm too old to do these things. How to I convince my patents to stop my swimming lessons

Answer: 
Uh it sounds like after 5-6 years of swimming lessons you'd be able to swim yea? hahaha Tell them that: - Its affecting your grades - You need more study time (even if you're a good student, same for the first one) - You just plain don't like it anymore - The Chlorine is burning your eyes and everyone thinks you're a massive stoner cus you have red eyes! - You just can't take the pressure to move up anymore - You don't have any free time anymore - You have other interests