What I found with my son is that for everything I knew he had done - there were 20 or 30 things that I didnt know. at this point I know far more than I need to and we have an agreement that he just doesnt need to tell me anymore. He has agreed that someday when he is an adult we'll sit down and he'll answer my questions. Denial is not just for the addict but is also something that affects us - it takes a while for it to sink in. We cant help but have those thoughts of "not my child" or "this isnt how i raised them" "maybe its not so bad." Sure there is that rare drug addict that can later on handle having a drink here or there but for now she needs to keep her head clear and get her strength back. Its too soon right now to even be thinking about what she can and cant handle.
The fact that she already knew where she wanted to go is a huge factor - why would she be thinking about rehabs unless she had a problem that she felt she could not control. Every person is different and everyone's behavior is going to be different. Just because she doesnt act like another addict you have known doesnt mean she isnt an addict - even if she feels like she is loosing control to drugs she needs the help. 20k is crazy expensive but i've seen costs like that for the nicer rehabs in my area - there are other options that are cheaper. I've never been able to afford the nice rehabs for my AS but did find lots of places that were charitable organizations or government funded. You could check out the database at the
Substance Abuse and Mental Health Services Administration (SAMHSA) Website - they have a pretty extensive database.