No conclusive answer on why it says January. An answer could be your order substituted a stock order, but that is speculation.
If progress goes like it SHOULD, you should go to 3100 this week, watch for GMConnects tomorrow morning. 3300 then 3400 sometime next week, and this is a pure guess, but assembly the first week of March 5.
Orders often but not always progress in a standard way. So far turbo LTZ orders have rarely progressed in that way, but if yours does progress well, my guess is as good as any. Ordering and waiting is a true roller coaster ride, so lay back, hang on, and enjoy the ride. From my point of view it is worth all the anxiety that comes with it.
Laborsmith