>I was 16 when I met her dad he was 22

>it was healthy to begin with

These two sentences don't mesh. You may not have seen it then, and even now, but a healthy 22 year old isn't prowling sophomore lunch hour

>She said given her age she doesn’t want to formally diagnose her just yet but given her dad who has BPD..she thinks something it could of been passed down to her or it’s trauma Induced behavior.

Quite likely, so don't blame yourself for it happening. All things considered, you caught it early and are doing well to provide support. Sometimes it is the case that we are predisposed to mental health problems, and more often than not we get hit hard in our teens or 20s and have a struggle recovering or just managing to survive. You're doing fine and I believe you'll make the right choices