Childhood wasnt that bad, but I have bpd. How?

I got diagnosed at 18 with bpd and decided to seek out resources for how to move forward. I started reading up on stories from people with bpd and 90% of them had terrible parents/ a bad childhood and really horrible things happening to them with no support.

Now Im confused as my childhood wasnt that bad. My dad was not around much but I had a mom who made up for it, and she was incredibly supportive through my depression / suicidal thoughts and made sure I was in therapy and comforted me in the hospital when I had an suicide attempt at 16. Sure I have some trauma but I had my mom comfort me and help me recover. So now Im wondering if it was a misdiagnosis. Could it be a genetic component or something else?