This is a little long so I'll try to sum it up for a TL;DR
My best friend has an issue with aspects of my personality that are affected by my BPD and I don't know how to fix things or talk to her about it in a way that won't set me off :c

While I was on a trip for my birthday this year with my bestie, she caught me off guard with some issues she has with me...issues that I'm sure my BPD causes. She was acting really weird and distant for what seemed like no reason and when I finally got it out of her it turned out it was my fault.

She told me that it seems like I only care about things I like and that whenever she talks about things she likes I don't seem interested. Her main reason for thinking this is because I don't have much to say about these things. Now this part is true because she is into some things that I have 0 interest in but I try to actively listen and give input when I can. But...most of the time I have NO idea what to say. I don't want to fake being into things...but I'm trying to be polite too.

I know I can be pretty self-absorbed about certain things but I had no idea it was bugging her. I have memory issues too and so I don't do well with certain details about people's lives (like their major in college, what exactly they do at work, where they just went on vacation). I do make an effort to learn and remember certain things when I feel it's important but most of these things aren't. She criticized me for this and was giving me relationship advice (that I never asked for) because apparently I was fucking up because I didn't know enough about my boyfriend's life/family/etc. This relationship has been the best and most successful one I've ever had and I think I've been doing a fine job getting to know him. It really pissed me off that she was telling me what I needed to do.

I know I'm not perfect and I'm working on getting better but it started to push me into a splitting episode. I was so furious at her and the way she approached me about it. I don't know how to explain how my brain works to her without her being judgmental and preachy. I love her but I don't know how to handle this kind of thing without it getting really ugly due to my anger.

Any advice is greatly appreciated as I am newly diagnosed and haven't had therapy treatments yet to help me deal with such things.