Hi,
This will involve trial and error and please don't be too hard on yourselves when the errors occur. Boundary setting doesn't happen overnight.
It seems she is amenable to get help . Is she currently in therapy while she waits for an opening?
If so , can you and therapist come up with boundaries together for her?
Other ideas- 1. would it be possible to limit her electronics at night- phone , laptop removed and put in a secure location? This may inhibit night time plan making with friends. 2. I am not sure if this is possible , but can you still talk to your daughter about your concerns ( sometimes they are too dysregulated for this)3. really sit down and think about the consequences for the boundaries and if you can enforce them. 4. I don't know if she drives yet, but if she does, no access to the family car , hide keys.5. There is a link / drop down menu at the top of this forum page on boundaries . Here is a link from NAMI on boundaries
https://www.nami.org/Your-Journey/Family-Members-and-Caregivers/Maintaining-a-Healthy-RelationshipNAMI also suggests rewarding good behavior in the link as well. 6. Is it at all possible to plan a fun day/ a hobby with your daughter ( I know, I know defiant teen with BPD , this may not be possible) . My thinking is this may ( or may not) put a good memory with you in her head and give her food for thought.
Please keep us posted we are here in this togehter.