My grandson who is five sews on an old vintage Singer. Can't mess that one up, can't even move it. LOL I showed him how to use it and not get it unthreaded and turned him loose. I don't hover but keep an eye on him. He sews fabric squares and strips together and usually ends up with something fun he created. He started using the machine with no needle to get over playing with making it go and feeding fabric in it. Now his three year old brother is in that phase of sewing with no needle. Young kids learn fast and remember the first way they are shown. I make sure to show them the correct way the first time and each time afterwards.