The Day That I Grownup (All Except For My Outters)

For the longest time I was five-and-a-half. I remember I was five-and-a-half for such a long time I thought I would never be older. But the day came.
Yesterday, I was 'almost six'.
The story is about a little boy, Zachery, who is six. He discovers that growing up is more about overcoming fears (his 'inners') than physical changes (his 'outters').