I'm a newb who just got through Lisa McCormick's begginer lessons Chapter 5. She teaches the beginner Bmaj chord as 2nd fret first string and 3rd fret of second, third and fourth strings. This has us starting to strum on F#. Why is that? Every other begginer cord starts on the fundamental. Why doesn't this one? Especially since the 3rd fret of the 3rd string is B. Why not just start there? Thanks!