One thing that has surprised me as my kids have gotten older is the number of suicides in the high school age group. All males though. One fellow used to play here in the afternoons with my son. I just don't remember much of that growing up. I can't think of a year that there wasn't at least one in the last six or seven years. The effect on this one family I know best was brutal. They remodeled the home to try and lessen the mental image but ultimately moved out.
This tragic trend is like addiction in that it is does not discriminate. We talked with our kids as these things happened but they seemed to feel a need to seek solace more so from their friends. It's quite the unsettling realization that one's flock is of the age to have to face these things. This is no scraped knee.
With our kids we confirmed with them that they are loved and also reminded them of the guiding framework of faith within which we operate as a family. Perhaps most importantly we stressed the importance of communication with us as parents at those times that they feel overwhelmed by life.
I kid about getting older, but I had to learn many many life lessons the hard way and would not want to relearn any of them. There seems to be more of a feeling of insecurity pervasive in the world than when I was a lad. Growing up is hard enough as it is.
I'm very sorry for all involved in the loss of this young lady. There will likely be some sort of service that your daughter may attend if you think it appropriate. For our kids, it seemed to be cathartic and helped them move on.