Ming from Agents of Speech explains why speech-delayed and autistic children struggle to describe past events. The ability to talk about 'then and there' is a later-developing skill. Understanding time reliably doesn't emerge until around age 5 or 6.
Chapters
Why your child who is speech delayed or on the spectrum cannot tell you what happened during the day. So I get this question all the time. The first point Is your child able to talk about the concept of then and there? When children just started to acquire language, they can only talk about here and now. Things are happening right here, right now in front of me and then is a different concept. They probably don't have the concept to talk about. The timings for a child to answer the when question is harder than Y, which is like around 5 to 6 years old. When a child can truly understand the concept of when. Time is a hard construct and a concept to grasp. So that's my first point.