My sister is showing signs of BPD?

Hi! Context ofc. I’m 21 F and am diagnosed with BPD since I was 19. My sister is 15, and is showing many characteristics I experienced at a young age. I’m still new to this, and have being doing DBT and getting medications to help the symptoms. Growing up childhood was very on and off, and then recently our mother passed away. I think that triggered something different. My mother was 100% the root cause and now that she passed my sister and i feel weird. Im going to see my therapist tomorrow and ask him also, but bpd sucks and i worry my sister may suffer also. Is that a crazy thing she may have it as well? I was told the common thing is is childhood trauma, abandonment and such. I would argue she had it worse than me. I try to be there and i just wanna help her so much. But when she catches an attitude i also full out crash out so i feel like im not in the best position to try to help someone else yk? I share advice sometimes i cant even listen 2. lol Idkk