Physics is Weird

E=mc² implies that as you accellerate, your mass actually increases.

If you were in a spaceship that could gradually go faster and faster forever without concerns about fuel or anything... you could never get fast enough to reach the speed of light. As you got faster, your mass would increase and slow you back down a little. (Accelleration is not speed and applies in any direction.)

Light can go the speed of light because light does not have any mass. It is thought to be the only thing that is massless in the univese.

We can go the speed of sound because sound has mass.