i hate to say it, but she's 17 (therefore approaching 18) and is moving out of the part of her life where you can successfully protect her from her own bad choices.

you can try to intervene all you want, but quite frankly there are some people that can only learn some lessons in life the hard way and will reject everything you do even if you manage not to come across as controlling and condescending.

you cannot help people who do not want your help.