Hi Sheneedshelp
I know that it will be difficult for you to delete your daughter from facebook as you are obviously hoping to use it as a lifeline with her but I promise you, if she needs you, she will definitely be in touch and presumably she knows where you live or has your telephone number.
I personally think you should delete her because its not doing YOU any good. It must feel like rubbing a sore wound every time you see her 'partying' and no good feelings can come from that.
My own DD20 deleted me from her facebook as she didn't want me to see what she gets up to out partying with her friends. I think she did the right and healthy thing. I am still on my eldest DD23 facebook, but we both live in different countries, she doesn't party and its another way of us keeping in contact.
I have just separated from my AH (23yrs) and deleted him straight away. I am going NC and I am going by the principle of 'what I dont know, wont hurt me' - that's a good saying for this situation.
Detach from this situation and hit the delete key! You know that though - its your gut reaction.