I am guessing they'll have their own "event" around the time of E3 or soon after to promote NX officially. Nintendo's been weird about E3 in recent years anyway.
As strange as a March console launch is (missing holiday craziness), I am super okay with it. I didn't want to have to choose between PSVR and a new console, so this gives me enough time in between to justify both purchases. I'll buy it day one because I'm not a smart consumer.