It's not the obvious maturity of her form that impresses Kakashi the most, although that he certainly notices; it's the determination in her bright green eyes and the two small scars scissoring above her lips that strike a chord. This growth is noted with mixed emotion. The copy-ninja cannot quite quell a sense of pride for her accomplishments, though he played but a minor role.
She smiles at him over her clipboard and dismisses the intern from the room with gentle authority.
He wonders why he never noticed her potential until she had already grown too big for him to teach.