The 10,000 Word Journey is for children of all ages, 2-17. We don't believe it is ever too early or too late to increase a child's word power.
As guidance, we recommend the following ages for the following products:
The Social Journey: 2-4 years old
The Narrative Journey: 6-13 years old
Storyteller's Illustrated Dictionary: 8-13
At five years old, children differ enormously. We have deliberately left that age group open, as potential Social Journey, or Narrative Journey, users. You know your five year old best, so you're best equipped to choose which product is more suitable for their needs, and who they are.