A weekly feature of Torah Tidbits to help clarify practical and conceptual aspects of the Jewish Calendar, thereby better fulfilling the mitzva of HaChodesh HaZeh Lachem...
The molad of Nisan is on THU morning. The first op for KL after 3 full days is Sunday night, March 29th - the eve of the 5th of Nisan. 7-day people will have their first opportunity for Kiddush L'vana on Thursday night, April 2nd, the eve of the 9th of Nisan.
Many people will probably wait for Motza'ei Shabbat HaGadol which has the advantage of being Motza'ei Shabbat (a favored time for KL) but the disadvantage of already being the eve of the 11th of the month, with not that many more opportunities KL until the deadline. That means that there is a chance of getting clouded or rained out of KL. So taking an earlier op is good.