A hard time letting go

I (19F) haven't talked to my mom willingly for almost 3 and a half years, I cut her off at 16 after realizing she would rather have a relationship with a man who abuses her and her kids than having a relationship and the love of her child. The last time I spoke to her was in a court to get my youngest siblings taken out of her custody. She absolutely ruined the relationship between me and my father and whenever I speak to him I know he has resentment towards me because I was the first kid he had with her (not to mention I look just like her) , my older sister was forced to parent me and my younger sibling because my mom was so neglectful and I know she also harbors resentment towards me because of it. I lost my one and only friend in highschool because my mom took me out of school and completely ostracized me from my community to the point I wasn't aloud out in the front yard without her being there to watch me. My bf at the time was the only person who supported me and even that, she manipulated and convinced him of so many horrible things about me and took private and personal things and used them against me when talking to him. She let her own bf physically, emotionally and psychologically abuse me and even rip patches of my hair out after physically assaulting me. For some reason among me and my two other siblings I seem to be the only one still holding on to the hope that one day she'll turn around and be a caring mother. Recently my birthday passed and she didn't wish a thing to me, but didnt hesitate to say happy birthday to my youngest siblings and even my ex boyfriend from highschool. I can't grasp the fact that my mom hates me and wants the worst for me. It's evident in everything she does and yet I still cry and pray that she'll say she's sorry for all she's done to me and my family and be a loving parent to me. I want to be like my siblings and have resentment and hate but it is so hard because Im convinced of what she could be. I just don't understand why I harbor so much love for someone who has hurt me my entire life.