and where did this come from?

...putting Ryles to bed last night, and she starts talking/pointing to her "pectorals, and biceps, and triceps, and trapezoids"...and she is pointing to the right places. i'm like..."uh...what?" where did she learn this stuff. i never knew that stuff when i was 5 years old. and then, when we were discussing cleaning her room, she made made a point to say that our room wasnt clean. hmmm... I can tell that future arguments are going to be testy with her...