Haunting Present

I can't say I didn't think it would happen. I'm not stupid, I know people change. But is it okay to say that I didn't think she would fall so quickly? I always knew she never go to far past college; despite the fact that she was determined when we were in elementary, and even intermediate school. However, in Jr. High, that's when I started to realize that she never really would go anywhere, no matter how determined she was. It was then she started to want to not be what everyone else wanted of her, including what she wanted of herself.
Last night, I saw this change I always knew would happen. I had seen hints of it before, but last night, it came out full throttle. She first started talking about how she 40 hours of work this week, but she was only going to tell her roommate that she had 20 so she wouldn't have to pay the full half of her rent; she would rather buy something new for herself because she hadn't bought herself something in a long time. Then, she kept wanting to get some jäger to drink. I understand we're college students, but do we have to drink all the time? No. And then, this is when I really started to get annoyed, she heard about a party in a not to safe part of town and get drunk. Drinking to get drunk is the stupidest thing I have ever heard, especially from a well educated, young woman. I had lost all faith. When she asked if I wanted to go, I told her no. I only wanted to get together with her and have a girls night, just like old times. I was okay if she wanted to have a drink or two, but I was not about to go to a party where I knew no one in a town where I don't feel safe, and then to get drunk, this was not what I was looking for. I told her she could go if she wanted, but I would just go home. I could tell she was pissed. This was not my friend. It has been ages since I called her my best friend, but now I don't think I could call her a friend.
What pushed me to the edge when she started talking about getting high. If you know anything about me, you know I have no tolerance for drugs. I've seen firsthand what it does to a family and what it does to a friendship; I've lost two relationships that I could care less if I regained because they were stupid enough to do drugs. My friend knows this, she was there when I went through these problems with those two other people. And yet she has the nerve to tell me that she wants to get high. When I told her this was stupid and not to get involved in it, she said that she had done it before. I asked when and she listed five times that she could remember, and I could tell it was a lie. She was not my friend anymore, and I had to spend the night on her couch.
I know I can't change her, but I won't let her change me. This is not a friendship that I will care too much to lose. We had 11 years of friendship. I will let college and work and distance separate us and I will be okay with it.