I agree with Quantum2003. The only thing that matters is what writing looks like in your DS's first grade class. What are their expectations as far as written responses, etc?
DD's school places a lot of emphasis on the content of what they write. They are expected to write very short stories with events in a sequence. These kindergarten kids write very well using inventive spelling despite sometimes not being able to read (which blows my mind). Handwriting is another story. There is a huge range of that. From what I can tell, they all seem to start writing as well as your DS sometime between K and 2nd. It just clicks. I have just been blown away by writing development in DD's school--DD included.
