I started my grands out sewing when they were three. I have a vintage Singer machine that I took the needle out and let them feed fabric strips. Mostly to get the feel of the machine, get the go fast, turn every knob, out of the system. When they could keep the fabric strip somewhat even I then put in a needle (about 4 years old) and bought a needle guard . All can sew a pretty straight seam now. The oldest is 8 and can thread and sew on my new machine. I have a grand age two who will be starting to sew this year. One thing is show how to do it correctly the first time and that is how it will be done by them and leaving a long thread tail is a time saver. LOL