Buying ps4 games online even though you don't already have a ps4?

So I currently have a PlayStation account (from my PlayStation 3) signed in to the PlayStation Store. I'll get a PlayStation 4. The problem with me now is that there's a game on offer that I would like to have. Which is reduced to -80%. The offer is unfortunately only up to 1 week. And my ps4 is out in over a week. I could buy it with the account I'm signed in to. But when I buy the game I don't know if it will get on my PlayStation 4 when it is there. Or can you buy ps4 games online even though you don't have a ps4 yet?

So if you buy it via your app or in the store and your ps4 comes, the game is in your library.

Yes that's right

Thank you, very helpful!

Gladly ^^