I told DH that I thought DS#2 was that. And that you could tell he was a child of older parents. DH took exception to this but I don't think it's a bad thing.
DS is quite an earnest child, he talks about things in great detail and isn't easily distracted. Don't misunderstand me, he laughs a lot and is a happy little soul, but he does tend to go deeply into things. He doesn't have lots of friends although all the children at school like him, but he gets a bit mithered by big noisy games with lots of people and much prefers to have one best friends than a host of them. He is quite young in his interests - fascinated by animals and dinosaurs, even though at 6 many of his peers have moved on to TV programme characters such as Ben 10 and Spiderman. Some of the children tell him that is babyish. He likes his own company and can keep himself entertained for hours with a few model animals and imagination.
That's what I mean by 'quaint'. What would you call it?