That article is based on anonymous sources ("according to [people] familiar with the preliminary findings").

It doesn't mean it's wrong, but it's not an official confirmation by the US government, and it only speaks to the responsibility of the strike, not the various claims of "killed children".

Those sources don't say anything about casualties, or the presence of children. The NYT does its best to make it sound like they do ("responsible for a deadly strike"), but so far the only source for how deadly it is, remains the IRGC. And the NYT happily quotes their claim that the death toll was "at least 175 people".

For what it's worth, I personally believe the US is responsible for the strike. I also think the IRGC is lying about casualties, but there's no way to know for sure, and a US investigation probably won't tell us more on that point.