I was in college when I lost my virginity. I wish I had saved myself for my husband whom I met a year later. I know there is temptation out there, but all I can do is teach my daughter our values and expect that she will remain close to her professed faith. I monitor my children's activities and friends very closely ( that's how I kept my virginity as long as I did...my parents had me under house arrest...) But I WILL be a mother-in-law before I am a grandmother. That is my expectation and I have no doubt it will be met.
You're wise to emphasize communicating values rather than going for "house arrest" which can lead to rebellion at the earliest possible opportunity. :)