How do I know if my daughter has BPD?

Everything I have read seems to point to BP, I really don't know if there is a chance with a relationship with her as I don't know how to deal with her.
Everyone who is close to her cannot live up to her standards, she treats us disrespectfully because we don't meet her expectations. Yet people who she works with or friends think she is friendly and self sacrificing.
She will tell me she is perfect and a lovely person and can't see why others can't be more like her. I can't answer her but have to stay silent, as this is normally said after she has shouted and sworn at something that has happened.
When I am with her I find myself feeling despised, just tolerated because I am her mother.
Her boyfriend tells me it all about her and he gets no consideration, things are only good when he is doing what she wants.
Her children have insecurity problems and are very manipulating, although she is the only one who can't see it. When they treat her badly she cries to me, if I try to help she tells me she loves them so much she has to give in to them.
I really don't know how to get to have a relationship with her that is not confrontational.
Close family members now only bother with her when she contacts them, as they find her attitude too much to cope with.
Thank you for being here

only a dr could tell her that hon. to me though it sounds more like narcisitic disorder. still though a dr would be the only one to diagnose that.

as bebop said we can't diagnose someone here, only a professional can, but i have to agree it sounds more like narcissistic personality disorder to me.

Thank you for taking the time to read and reply, I appreciate that.
As far as a doctor that is where I hit a brick wall as she thinks everybody else is wrong and if everyone treated her properly she wouldn't be stressed and life would be perfect.
I am trying to read up on BPD but now will go to Narcissism. I want to know from reading how I can deal with it and how to avoid confrontation that seems to arise from nothing. If I keep quiet I am accused of not caring, but sometimes she will ask for my help and when I tell her what I think I would do in her situation she takes it as critism. On her own admission she can't take critism.

Thank you again