Hi Grace43,
I want to join everyone else and say Welcome!
I know it's scary to talk about the situation with your mom because your whole family dynamic has been to hide these behaviors from the rest of the world, but this is a safe place to talk about it. We all have someone the BPD or BPD Traits in our life and we get it.
My brother was rebellious and refused to listen to it, so she would not display as much anger with him as he grew older.
In the dynamic of your family your brother was "rebellious" but to me it sounds like your brother has boundaries when it comes to your mom. Refusing to listen and buy into the invalid stuff your mom was putting out there.
Having/creating boundaries are an important tool.
She was very critical of me and of others (my dad)... .My mother is a perfectionist and wanted me to be perfect. Her "constructive feedback" was her way of loving me... .she told me that she couldn't understand how anyone at our church loved me because I was a big nobody.
The above stuff is so painful each comment and criticism cuts like a knife.
I don't have a BPD mom but have a very critical mom and like you my self esteem struggled along with my struggle to be who she wanted me to be. The thing is you are good enough, perfect enough, just the way you are, in your own special an unique way. By trying to fit into her mold you are putting a lot of pressure on yourself and causing yourself a lot of anxiety. No one is ever perfect, let it go and just be you... .your authentic self... .Says the Panda that took 47 years to learn this

I finally figured out that my mother's idea of perfection had more to do with her than it did with me. It had to do with how I reflected on
her, how I as part of
her family looked to the outside world, and how I lived up to
her idea of perfection. I'm very different from my mother where she is intellectual, I'm creative for example. I finally came to realize that I like who I am and that I will never be who she wants me to be and frankly she will never be who I want her to be and that is okay. Now when she gets overly critical or controlling about something I just let it roll off. It is about her, it isn't about me at all.
I just worry about my own parenting. I am so scared
This awareness is a good thing we can learn things from our upbringing but we can also unlearn things. The fact that you have this awareness speaks volumes in terms of your own parenting. You experienced things as a child you would never want another child to experience you know where the line shouldn't be crossed, you are receiving therapy, there are parenting classes out there if you're looking for more support. You will love and raise your child your way if you choose to become a parent. You are not your mother.
Thank you all for the support. I spoke with my mom today and she was in such a great place mentally. I immediately felt extreme guilt and sickness over posting about my past with her. I tried to come back to delete it.
I'm glad your post is still here, the guilt is very normal, people with BPD use what we call FOG (Fear, Obligation & Guilt) or emotional blackmail to get what they want. You most likely have grown up with this, along with the whole family dynamic of hiding anything that the family defines as negative. But it is your truth and your experience and truly it is okay to share, particularly here. Your needs and feelings matter and it is okay to put yourself first, it isn't selfish, it is self care. Stuffing your feelings, and living the way someone else thinks you should live in my opinion isn't healthy... .no wonder you had IBS and have migraines... .so much pressure to be someone your not, and not feel the things that you feel.
I'm really glad you've landed here and jumped in an posted. Keep it up, keep talking, keep getting it out, we will support you and by sharing you support others.
Panda39