at 17 are you sure that she can't just tell her mother that shes sexually active? btw kudos to you both for being so paitent. how much older are you then her? i dont think doctors can tell if youve had sex or not so couldnt she just tell her mom somethings bothering her down there and go get it checked out? i mean there are otehr things besides sex that can make your hymen break...tampons, horseback riding ect... its great that yoru so concerned and want to learn.
and past that mini rant i agree with mal..you have done all you can