IIN That I remember being this young?

I thought the same. I was 6 in 2001 and was in kindergarten when 9/11 happened (and remember being in class when the teachers found out, too; it was a scary and confusing day for a young child who didn't fully understand what was going on).

Perhaps they meant preschool? Though when I was in preschool, it was still 4- and 5-year-olds. Or perhaps in some places kindergarten includes various ages? Not sure.