Two of my daughters did the same but separately.
The oldest went with her boyfriend, now her husband and went to India, Malaysia, Thailand, Ozzie and new zealand. Learnt a lot and now live in Ozzie with 2 kids.
My youngest went with a friend to Mexico, USA, Jordan, Singapore and Ozzie, where she met and married her now husband.
As long as she is aware of the dangers and keeps in contact with you and friends she should be OK.
There is a web-site where kids can keep in touch with family and friends, but cant remember the name.
Will have a search tomorrow for you, as I know how concerned you are, as I was the same.