March is the month that has been communicated over the last few months, but without a specific day. So the 21st is new info. Last year it was announced production would start in February (also the 21th). Let's hope the date now holds up. I do think a 'mid-year start' of deliveries is too pessimistic though. It should take about a month after the start of production for the first cars - from the signature-series - to reach customers.
I heard dealers from all over the world will get test drives later this month in California. Ten international journalist have also been invited, so hopefully we can read the first real reviews early March. I wonder who got selected.