Perhaps they planned ahead for a potential inclement weather set back, hence the early start on construction. Now even if they did plan ahead there is probably a relatively small window of days they can go without vertical construction. Given the unseasonably warm winter thus far I'm sure the climate has been paramount in the amount of construction that's been occurring.
Keep in mind, too, that the marketing campaign run on this coaster began unusually early given the parks track record. (I'd exclude Pesto's train wreck of a "campaign" for all intensive purposes.) So hyping up an attraction of this magnitude would be a bit irresponsible on the parks part if they aren't aiming for an opening day debut.
However, since a date hasn't been set in stone it shows that management acknowledges that anything can happen to push back any time frame they may be aiming for. Typically we get an announcement aligned with a major weekend like Memorial Day.
I could go on and speculate for hours, but I'll spare ya'll the time. Me personally, I'm keeping my fingers crossed for an opening day unveiling.