Well this is what happens when I start feeling creative and go right into something. Character Ideas run through my head.  So I put a character together. In all honesty I thought ANBU were at least low as chunin level when I was thinking the character up.  Its not often in canon they went into the ANBU, unless they were dealing with the ROOT.   Or dealing with Uchiha storyline stuff, or Obito/Kakashi storyline stuff.