Mary makes a mistake by "defining down" the actions of God to just what Jesus apparently did (or didn't do) in the 4 Gospels.  She says:  "We can’t ignore the fact that in the four Gospels the only times we see Jesus obviously change his mind."

Jesus is God. 

Someone, a sister in this case, is always trying to shrink the world of God down.

What about God in the case of Abraham, about sacrificing his son?