Heather, this was great!
I think a lot of our kids here lean towards Borderline (BPD) and it often gets confused with bipolar. I'm really glad you brought up your daughter's diagnosis. I didn't know I had borderline at the time, but now that I know (interesting story on how I realized it), I can see it in many younger kids...at least many are heading toward it. Kudos to you for believing you can get this diagnosis. before eighteen. I think so too. I had shades of it from a very early age. I'm starting to question my BiPolar (BP) diagnosis.
Keep letting parents know this is a possible reason why their teenager, in particular, is all over the map, confused, cutting, substance abusing...etc. There is good help out there now.