Omg i srsly dont know what to do

So, i was really lonely like awhile i go and made a new friend that happened to have bpd, it was going really well, but honestly, they were making me quite uncomfortable. However, im not the type of person that easily defends or sets boundaries but like just now they got upset at me and i dont really know what to do? should i set boundaries? but honestly i dont think that being friends with them would be good. BUT I WILL FEEL INSANELY GUILTY AND I HAVE EXAMS soon cuz im sec 4 and it might affect me, however, uhm we both live in the same neighbourhood and im scared they will like find me if i block them!! and honestly im just upset cuz i feel like we could be good friends if i could get space and honestly, i dont get space, they even understand my need for studying and makes sure i am, which i am grateful for.

I JUST DONT KNOW WHAT TOO DOO cuz im at a really horrible time in my life and i feel like this is making me worse.