B,
Good for you for reaching out for help. I started dating my axh when I was 15 years old. If I only was as smart as you, when I was your age. I put up with 34 years of drugs and alcohol abuse, lies and everything else that goes with addiction.
You have your whole life ahead of you. Please move forward and let her figure out her addition. It is a one person job.
Sending hugs and support to you my friend.