Its hard not to worry about them. It is also hard being a teen at this time. They are trying so hard to find where they fit that they will do things that they think are cool at the time, but may not be so happy with later.
Peer pressure is also hard to deal with too. When I went to high school smoking ciggarettes was the only thing we were really pressured into & I was never pushed.
These days they are sneaking alcohol in in their water bottles & smoking pot in the toilets. Not to mention other drugs.
I hope she realizes that she can be happy just being herself soon & not feel the need to please others as much.
Good luck.