Prose Merlin

At the beginning of the passage of Merlins birth it is said that Merlin has the body given to him from the devil and the mind and soul given from God. A point is brought up that Merlin will have to choose which path to go down(the devils or God). However, right after his birth he is baptized, by doing this did it affect his decision or was his decision already made for him by baptizing him?