You don't need a stitch regulator but it will make the learning curve easier unless you just happen to be a natural.
I started without one and used my foot controller to control the speed. I taped it to the handles and just pretended it was a motorcycle--slow down in the curves--speed up in the straight aways--and I did all right. I tried just setting the speed & using my start/stop button but I did much better squeezing the foot controller.