What do you make of Trump's decision to postpone the State of the Union speech until after the shutdown?

It caught me off guard. I thought he would find some other location for delivering the speech. On the surface, it looks like he is caving in. In the tweet where he made his announcement, he did not say anything negative about Pelosi. He said that postponing the speech was her “prerogative”. Is this really Trump writing or a member of his staff? Is the word prerogative even in his vocabulary? Why hasn’t Trump made up a derogatory nickname for her, as he does for everyone else he disagrees with? Is he intimidated by a woman? It seems so unlike him.