Welcome Runnermom,
We are very afraid for our adult BPD making the wrong choices that could change their life trajectory. It is terrifying, actually, as we have loved them and tried to protect them growing up as all parents do. The good news here is that your daughter is open to treatment. Hold on to that. You had mentioned "we are trying to figure things out". My suggestion is you transitioning over to " she is figuring things out" with you stepping into the background. As painful as this is, it is that time. Here is some suggested reading to browse through and consider:
https://bpdfamily.com/message_board/index.php?topic=332045.0 You can offer advice ( If asked), but accept the fact the final decisions are hers to make as an adult . This is gut wrenching, I know. Please write back , we are with you in this journey and you are not alone.