Where is FaceTime on IPhone 4S?

I got the 4S about two weeks ago, I still haven't been able to find FaceTime. I've asked Siri and she said it wasn't in my apps, so I tried to download it, but it wasn't in the app store.

Face time isn't an app for the iPhone 4S, it comes pre installed, make sure it's enabled in your settings. Settings > FaceTime
It should automatically work, make sure you have an apple id linked
If the problem persists
Repost on here and ill come back'

FaceTime is embedded into the OS. If you know of other person with a FaceTime enabled device go to his contact sheet in the Contacts app & on the bottom you would see a FaceTime button. Tap that to start the call.