why time isn't in relation to the speed of light. i need opinions.

everyone always talks about einstein's famous theory of relativity. i think the guy was a genius (like most people) and i agree with him on the subject. the only thing is that people always associate time travel with the speed of light. if you traveled at the speed of light then "time" wouldn't slow down, only the speed at which you see things would slow down. see what i mean? whoever said that light had ANYTHING to do with time? (well, maybe einstein...but not everything he said was correct whether or not we would like to believe it.) it's kind of like the sound barrier. people always thought that it was IMPOSSIBLE to break the sound barrier. now we are designing jets that will be able to go mach 25. My point is that anything is possible. People will say things are impossible until they or someone else is able to prove them wrong. so back to the point of the sound barrier. sound travels at somewhere around 800 mph right? so if a jet was going faster than 800 mph then why aren't they time traveling? my major point is that time is not in relation to the speed of sound so why would it be in relation to the speed of light?