[EZ2Luv]

Gosh that is one tough situation to be in, but only you know what is right for your family. This girl does have some problems, is there any way you could stall the actual adoption? I wouldn't rush into anything lkike this situation if it were me.
I am no expert, but I heard some wonderful advice when adopting children with problems. Ask yourself if you would adopt this girl if this is the best it would ever be? In other words would you be willing to live with her exactly the way she is now. Unfortunatly with these kids there is no garentee that things will ever get better, she may keep this attitude until she is out on her own. If you are will to accept this girl as she is, attitude and all, I would say go ahead with the adoption. However, your words tell me otherwise. Alot of times people go ahead with adoptions in hopes things will change once the child is home, sadly this is not always the case and in some situations thing get worse. I am not trying to frighten you, but some of the greatest of parents here have experienced this and have exhausted every avenue of trying to help these kids change and it just doesn't happen. Also, her age has alot to do with it. She is so used to these attitudes and defense mechanisms(sounds like she has some walls built) that it might be too late to expect much change.
Personally, I agree mentoring might be a better option.

Good Luck
EZ