Talking to adult children

Hi Coaches,

I am concerned about the lifestyle my daughter is participating in presently and I am wondering how I can talk to her without having a manual for her. She is 19 and putting herself at risk through online dating, and using drugs and alcohol. I know adults can chose to do what they want, but I am wondering, since I am still her mom, if I should talk to her irregardless on how it is received. I am having a hard time not saying anything because she is under my roof and I worry about her. Is this still wrong?