Here is a photo of Katya / Katherine dated 1922. I have have only one family letter in my possession that is translated from 1919 that states she was 4-1/2 when they left St. Petersburg.
On the back it looks like adult writing at the top for the date and the message from the little girl. I like how it shows how she is learning how to write with the lines ruled in as a guide.
Back of Photo: