Does the Length Change depending on your arm length?

Actually, no.  

Arm length does not change the appropriate size recommendation.  Whether you have long or short arms for your height, the proper hand positioning is exactly the same.  Your hands should be at hip height, about 8″-12″ from your body on each side. If you have longer arms, try bending at the elbows a bit more to keep your hands in the proper location, but you should NOT get a longer rope.