Yep same thing over here in Germany.
I guess Meta is making some sort of beta test in the US first and after solving all those different international data protection legal things the feature will be rolled out over time in the different regions.
And I don't think that Meta should hurry. I'd prefer a properly working calendar integration rather than the risk of "losing" or forgetting some appointments and dates due to rushing and time pressure.
However, I am also looking forward to seeing the seamlessly integrated Google calendar in the Meta AI-App:)
Have a great time meanwhile;)