Watch the start of any take you have filmed. Before the first real word there is almost always something: a breath, a smile at the lens, a “so”, a hand reaching back from the record button.
In a long video that second is nothing. In a short it is where most people decide to leave.
What we do instead
We start on the first word that carries the point, even if it is mid-sentence. If the point comes late, we move it to the front and let the setup play after it.
It feels abrupt the first time you see your own face do it. Nobody else notices.