Hi Ger93! I grew up in Bolivia. Small world.
So many people here can understand what you're going through. From the behavior you're describing, I can see why you think it may be borderline. It sounds like you're able to stay calm when she is dysregulating, which will really help you.
Have you prepared for the different scenarios you may encounter when you go to visit her? What are some of the possible ways this could play out? Does she have support?
It sounds like you've done some reading already. Understanding BPD has been incredibly helpful for me.
pj