First, the earliest "Sunday" Novus Ordo I've ever seen is 3:00 pm from a parish somewhere in Florida (I forget where), though 4:00 pm is more generally the earliest one usually sees.
When I was a child, the pastor at my parish resisted the Saturday anticipation Mass until he was ordered to implement one by the archbishop. He looked at the docuмent that gave authority for the practice and set the time for the anticipation Mass at 7:00 pm because the sun had set by that time when he implemented it on the first Sunday of Advent in the year he did so. In the spring, when Daylight Saving Time was to be put into effect and the sun generally did not set until around 8:45 pm, the pastor announced that the "summer schedule" would begin and Mass would start at 9:00 pm. The caused some issues with certain influential people who contacted the archbishop. Later the "summer schedule" was cancelled and the pastor told my mother that the archbishop had not even been happy with the 7:00 pm Mass, but had allowed it, but he was not permitted to change to a 9:00 pm Mass time.
Actually, the Saturday anticipation Mass began because, at or shortly after the Council of 1962-1965, the faithful were encourage to gather Saturday evening to hear the readings in the vernacular and hear Vespers so as to prepare for Sunday's Mass. These gatherings began to be scheduled and, in some locations, a more liturgical atmosphere was established that looked very much like Mass and some priests even began having a Mass at that time. Few people could see a reason to attend Mass on Sunday since they had just been to the same Mass the evening before, so bishops began to allow that the "anticipation" Mass (that had not really been authorized to begin with) fulfilled the Sunday obligation. The Vatican soon confirmed this new practice in violation of its own law. This is just one more Commandment (i.e., the Third Commandment of God) that the Conciliar church has abrogated.
I've always wondered about this Sunday evening issue also. I cannot understand how the Conciliar church can say that Sunday begins on Saturday at 4:00 pm but Monday doesn't therefore begin at 4:00 pm on Sunday. But this is also the reason the Conciliar bishops (in the United States) have cancelled most Holy Days of Obligation that fall on Saturdays or Mondays. The time issue is just too confusing and, frankly, arbitrary.
Church law (i.e., the 1917 Code) specifically sets the beginning of the day at midnight and no Mass can begin for a day before that time. Even the Holy Week changes of Pius XII specify that the ceremonies that proceed the actual Mass are to be scheduled to begin so that the actual Mass will begin as close to midnight as possible. There is no tradition in the Catholic Church for celebrating the Mass for Sunday in the evening before.
For those who say that prior to 1955 Holy Saturday Mass was celebrated on Saturday morning also need to realize that no one thought that attendance of the Holy Saturday Mass (in the morning) substituted for their obligation to attend an Easter Sunday Mass.
Stay away from the Novus Ordo on Saturdays or on Sundays.