We did not move to written narration until 5th grade, student around 10’ish. We tried 4th with out smooth success so we went back to oral narrations and about 1/2 way through 4th grade I start scribing their oral narration that way they practice having to gather thoughts a as well as pause to get them written down by me, but not loose train of thought 🙂
No need to rush into writing, oral narration are teaching them a lot about gathering thoughts, don’t feel rushed to get the student writing.