It should be available to everyone, but when it first came out I did have people let me know they did not get the update. It tends to be Android users that I hear from the most that do not get the updates right away.

Are you on iOS or Android? What phone are you using? Do you have multiple profiles? If so, have you tried on the other account(s)?

Here’s what I often do for troubleshooting (for iOS):

Log out of all Instagram profiles.
Delete App.
Force Quit all apps on iPhone.
Power down iPhone
Power back on.
Re-install Instagram
Log-in to main account
Swipe to Open Instagram Stories
Swipe Down to Add From Camera Roll
Select Wide Video (1920 x 1080)
Pinch in from corners to re-size video

Let me know if it works or if you have additional questions.

Best,
Mike