Anthroposphical wisdom teaches that very young children (age three and under, especially) do not experience the separation/ individuation of the 'I' yet. They see themselves as an extention of the mother, still. Using their name when speaking about/ for themselves is easier for them to understand and use. For example, a child would say, "Sara got hurt" instead of "I got hurt."
Again, this scenario occurs only when the child has been raised Anthroposophically. If the child has been raised with a parental focus on intelectual stimulation, the child's mind and mental processes will be more awake and sophisticated at an earlier age.
The earlier in a child's life they start referring to themselves as "I" the earlier their intelectual experience is awakening. In Anthroposophical perspective, this is not a good thing. It is a desire of this philosophy to keep the child in the ethereal, angelic realm of humanness until the time the child experiences his/her tooth change. That is believed to be the time when the spirit of the child fully enters the body and becomes grounded on Earth.
That said, it is therefore easier for the child to understand parents who say "Mommy is coming" instead of "I am coming."