My mom says its "wrong" to cut off ties with my crazy asian aunt

I am 22, recently college graduated with a job. Now that I am on my own and fully able to make my own decisions, I've been wanting to cut off all communication and contact with my aunt. She has no kids of her own and basically thought of me and my sister as her own kids. She's been there for us when we were little and I basically considered her a second mom until she started to show her true colors when I was starting middle school. She has been a very negative influence on my life because of her type A, sociopathic personality. She doesn't have any close friends and her ex-husband divorced her and called her a crazy bitch. When I was 10 years old she told me that my face needed plastic surgery and throughout my teenage years would tell me that my personality needed to be "fixed". Needless to say I grew up with low self esteem and self conscious because of her. I mean, on my 18th birthday, she called me and yelled at me for not texting her "Merry Christmas". She told me I was raised wrong and that I am rude. I cried my freaking eyes out on my 18th birthday. She is just super controlling and tries to make me someone I'm not. At my grandma's funeral, she would constantly look over at me to make sure I was crying. She claims that she just wants me to be happy and then says shit like "doesn't money make you happy". I look at her life and it is sad because she has no kids, no husband, no friends but a lot of money. And I definitely do not want to end up like that.

My dad used to defend me from her but then he died when I was 10. And my mom has a submissive personality and thinks that my aunt is just trying to help us in her own way and that we should just be good kids and listen to her. When I told my aunt that I got into a state university (Purdue) and accepted the admissions offer, she told me verbatim that the "school was for retards" and that she couldn't believe I was going to a school where "University of Illinois rejects go". I found out from my mom later that when we were kids, my aunt called my mom and told her to raise me and my sister to go to Harvard with no exceptions. My mom just said yeah yeah but really just let me and my sister do our own thing. Mom just wanted me to be happy which I am really grateful for. My sister got into Uchicago which is a school that is right up there with the Ivy's and I went to a state public school. After I started to attend Purdue, there was a huge difference between the way my aunt treated my sister and the way she treated me. She would go around and tell her friends about how great my sister was and how good of a school she went to and then talk down about where I went and tell everyone that my school is not good at all. She would buy my sister all kind of nice things but never me. I confronted her about it once but she insists that she treats us equally. She pays for my phone bills and has been ever since I was 12 and now I want to pay for my own bills and have nothing to do with her.

Now that I am telling my mother about my plans to cut off my aunt completely on all social media, e-mail, and on my phone she says that it is very very wrong of me to do so because no matter what, my aunt is family. I respect my mom and so I think I should consider what she is saying but at the same, my life would be so much better and happier without my aunt in it. I can't ever travel or make plans without my aunt trying to yell at me for not telling her about it or yell at me for not visiting her. She constantly asks me about my GPA and when I tell her I have straight A's, she just shrugs and says that its only because I go to an easy school. I am a pretty sensitive person so all these things combined have made me a very anxious person and I even get heart burn flare ups whenever I talk to her. She is just that stressful of a person. All she cares about is what others think of her and how much money she has. One time she told me that she wanted to "brainwash me into marrying someone rich and submissive." She is just not a good human being and I do not want to be influenced by her at all. I confronted her about all these things once before because it is a problem and she just said that she is not going to change because its a part of her personality and that I just have to deal with it. Is my mom right in saying that it is wrong for me to cut off contact or am I overreacting?