Teenagers are always trying to look like adults and act cool and all, like vaping and smoking, driving at high speeds, showing off there money and all to be popular, almost all of them are dare devils and want to show it off, that is why they would go out and party/drink all the time and get into other bad situations.
Now there are 2 sides of it, teenagers may be participating in good behavior and taking a risk at the same time. This shows there bravery, passion and how much support they have in thereselves/will-power.
she should know she is beautiful just the way she is . In my opinion outer beauty doesn't matter what matter is inner beauty. She just have to love and accept the way she is .Sometimes people should learn to appreciate themselves.