In her defense, I had my birthday party just a few days before and it was an unusual year in that school had started by (maybe even on) my birthday.
I remember feeling a bit disappointed on the day, but certainly not distraught or traumatised. I also never found myself randomly thinking about the incident after except for when my mom mentions it or from stories like this.
My point is that it depends on the person on how big a deal it was. Also, perhaps the parents do feel guilty about it, hence sometimes sharing it as a “funny story”, but I wouldn’t know.
My own 6 year old child seems to be neurodivergent (I suspect I am too) and is struggling a bit with pre-school, even now at a bridging school.
We first had to confront it about 2 years ago when the highly regarded mainstream school she was at said she would have to repeat the year.
At least for me as a parent, the possibility that my child won’t grow up to be a self sufficient is terrifying, so it was quite a bit to come to terms with.
Fortunately we weren't in denial and she’s getting exceptional assistance, but some parents definitely find themselves in denial when confronted with this situation.