Funny, also ordered on 12/15, my order shows the same exact dates, it does seem we will be on the same batch, BTW mine is 64 GB Gunmetal.
FYI, the Gunmetal showed "Ships in 14 days" yesterday, today back to 3 weeks, it seems new customers jumped on the bandwagon too quick and now bumped the "Ships in" again to another extra week. OnePlus didn't expect this phone to be such a hit, but with the Note 7 disappearing act and the Pixel so expensive (should've been a Nexus), this is the phone to have, especially when you look at all the YouTube videos beating any other phone almost easily.
I think since it showed 14 days yesterday, our orders may be about to ship, so the 3 weeks hopefully will be reduced for us to 2, we'll see hopefully tonight or tomorrow.