I understand independence. I have an older child too. But she is a girl. Does that make a difference? Or is it only boys that we put this cap on?
It sounds like I'm being disingenuous but really as others are pointing out to you, it's nothing to do with the sex of the child or the age. It's a personality thing. My dh, as I said, is 31 and endlessly affectionate with his parents. He says that neither he nor his brothers or sister ever started refusing to kiss/cuddle goodbye at school.
I just don't agree with the inevitability of it. And even if your child is one of those who moves away from physical affection or at least public demonstrations of affection, they share themselves with you in different ways as they get older.
It's like that crap people spout about a son is only yours until he gets a wife, as if a boy is on loan to you. Don't be disheartened. Embrace the changes. Find new ways.