My 2 local granddaughters started out at age 9 or so, on the Janome Jem Silver (ASG anniversary machine) same as the Janome Jem Gold which unfortunately has been discontinued and Necchi Travel Mate. It is a fantastic machine, sturdy, accurate & fast. Some dealers still have them & can be found online.
One granddaughter likes to sew slow & very precise but doesn't feel the joy. The other is pedal to the metal as fast as she can go, not concerned about accuracy or seam widths, But loves it and has gotten very creative, now age 13. She has finished at least 10 quilts, had a quilt in a quit show, an active junior member of ASG.
I can't say enough praise about the Janome Jem Gold or Necchi Travel Mate. A friend has a Juki, not sure of model, that is also a great beginner travel machine.