Hey guys, this is my first discussion post so I hope I get this right

This might be a bit long so I apologize but I really need to get this off my chest...
*back story*My aunty has been married for 6 years now living her own life. She is an identical twin with my mother. My mother got married first and she disagreed with her getting married (I'm still unsure why but the family have all said that she was jealous, she was bitch faced for the whole wedding, people were going up to her asking if she was alright and she replied to them very nastily... fast forward now I'm engaged and in love and all that good stuff.
My fiance asked my mother if he could marry me and she gladly said yes! This was a month before he proposed. I was on the phone to my mum and she told my aunty about him proposing, while I was on the phone to her according to my mum she gave a digusted look and then said "Well I'm sorry if im not jumping for joy". o.O, anyway thats not the issue, so because she said that I said to myself well I'm definately not telling you when he proposes since you seem so damn happy!! He proposed and I announce it on facebook, a few hours later I say you know what maybe I should tell my aunty let me be the better person, when I tell my aunt she texts me back saying a cousin of ours already told her...so I said well I am telling you now...and you wasnt that happy before when mum told you...she ends the conversation saying "Its fine you think your a big woman so you can do whatever you want"

Because of this my fiance does not want her at the wedding, neither do I. My mum said that its up to me but I should be
prepared for her tantrum and her rants to everyone, plus back talking about me...I really do want my aunt at my wedding because I love her so much but what she said was hurtful and quite frankly disgusted me. I dont know if I should invite her or not.....I'm 20 and my fiances 24, we both have stable jobs and are already supporting ourselves and we live alone. No one is helping us pay for the wedding.