there's a level of intelligence, awareness and creativity that really opens up in a kid around grade 3.
comparing 2nd graders to 4th grader.... it's no ccomparison. it's kinda the age where they fig out santa, they figure out life/death, finances, where babies come from, what drugs and alcohol are, crime, etc.
I've seen it in all my neices and nephews these last few years... a 2nd grader (7 years old) woudln't come up with what this kid said. A 4th grader (9 years old) certainly could. An 8 year old? It could go either way. Raised in a lez house, she may have a very acute awareness of the situation and facts.