You'll find that the geniuses in places like Budapest spent their youth thinking about number theory and discrete math problems. Calculus is something that takes a bit of a leap.
Nonetheless, you should be very proud, she is quite talented, as the link demonstrates. Have you considered something more traditional, like number theory or something more fun, like graph theory?
Actually, I think we're headed toward symbolic logic and Boolean Algebra. I'm trying to impart the lower division of a double major in two technical disciplines before she's 18. Other than using a word processor, she has yet to use a computer, so we have work to do there too. Basic electronics first. From there to gates (Boole there), assembly language, then programming. Frankly I think her talent would be law or accounting, but to be technically illiterate in this century is a grave mistake for any person wishing to consider themselves educated.