It's odd that it hasn't updated automatically as by default, it's set to auto update.
Just a thought but have you gone on the Play store app, tapped on your account (circle top right on the search bar), then hit settings and tapped on the About section? In there is an "update Play store" button.
I take it that you've already tried that. If so, you'll probably just have to wait until it's ready to do so on it's own. It could be because of different country variations and time scales maybe??
