When selecting a ski for your child, it's a good idea to choose shaped skis because they don't exert too much leverage on child's legs. They're also shorter and therefore easier to turn and manage.
When picking the length of the ski it is a good idea to consider your child’s weight, ability and how aggressive they ski and how fast they are progressing. A good rule of thumb is to purchase skis that roughly match your child’s height from the shoulder toe the ground.