I also ordered in January 2019, but from what I’ve seen estimates point to the purchase density not being linear and in turn order date is less important than order number for those of us farther out.
Based on the non-official estimates I’ve seen once we get past the November 2017 orders we should start seeing months of orders go out instead of days. It appears that there is a much higher order density in the first 90 days of orders than all of 2018.