First note makes a better story. :) And not totally implausible--she could have inferred the tempo from the preparatory gesture leading into the first note.
Teacher: Have you ever learnt Villa-Lobos étude #1? (Reaches for his guitar)
Me: this thing? (I play one note, very possibly a semitone off as it’s a reach past 12th fret on the D string)
Teacher: (with his back to me) No, that’s #4
Me: (wtf!)