How long do you wait before you change your relationship status on facebook?

We have been seeing each other for a few months and have agreed to become exclusive. I changed my relationship status a while ago on facebook, but he hasn’t (he doesn’t show his status at all).
I know it’s stupid and somewhat adolescent to be bothered about something like facebook, and also don’t wanna come across as needy or a facebook nerd, but I’d kind of like for him to let people know he’s taken and has a girlfriend.

If you have a facebook account, at what point do you change your relationship status?