I think I have allowed myself to integrate BDSM/Kink into a part of my identity that I can cherish. I have heard more people like Mistress Damiana Chi PhD talk about Kink as its own sexual identity. I still feel like I have to be careful who I share this identity with, but there is no need to look at it as some type of pathology, or something born out of trauma. It has just been a part of me since the girl next door started playfully hitting me with a stick when I was an adolescent. I wish someone could have started mentoring me when I was 18, or connected with good people in the BDSM community. Someone to say hey come on in there are a lot of wonderful kinky people.
I don't know if this answers the question about transitions of limits into either the hard or soft limit categories. I am surprised by some things that I enjoyed after experiencing them like tickling or hot wax. I think at this point in my journey I love playing with in scenes with a good story to shape the drama. I still have a hard limit with needles because I feel like I am going to pass out when my blood is drawn: I am afraid that it was be the same experience with a temporary needle. There is still so much to explore.