For some reason I feel like there are so many stories where Jesus becomes the “dad” of the group. “What are you arguing about”? I think when Jesus explains what needs to happen, He lets the apostles talk amount themselves, not interrupting their argument but fully aware. I almost feel as the the they kids arguing well your the “greatest” you ask, he likes you better, your His favorite! Reminds me again of my own kids afraid to be the one to ask a question where they are “supposed” to know the answer.
When Jesus picks up a child and tells them by tevieving a child you recieve him as well as the one who sends Him. Maybe the child is the best way for Jesus to explain, (especially in those days) the uncertainty of when somebody’s gets pregnant. They receive it and don’t ask questions. And that is what he is trying to explain. Receive what God gives you. Very much as Mary did the same. She accepted and received Christ!