Weddingbee boards

I was forced to make her my MOH by my mom.  She told us from we were small that we HAD to make each other our MOH'S.  But anyway, she's really pissing me off.  I swear if she wasn't my sister, I wouldn't know her cuz I would never want to be her friend.  She's 2 years younger (25) and completely selfish.  Doesn't care about anything about the wedding.  I swear I probably woudn't have had a shower if my other BM friends didn't take charge.  And now she's saying that she is NOT inviting this girl, who is invited to the wedding, and is in the circle of friends who are invited to the shower, because she doesn't like her.  She doesn't want to invite my fiance's aunt and 2 cousins, who I will invite anyway no matter what she says.  We (me, my mom, and her) were all supposed to go to Miami for last minute wedding shopping....like shoes, make-up, whatever we hadn't gotten yet.  And she's like, nah, i don't wanna go...(although my mom is paying!!)  She'd rather go AFTER my wedding cuz that's when her friend is going.  And now my mom doesn't want to go because the dog is in heat and she doesn't want it to mate with the other dog and she has to 'watch' her.  And then my sister said just go with my fiance, cuz he needs his suit, but he might not be able to go the same time cuz of his work.  And she's like..."ha, just good for you, go by yourself!"  I haven't even done anything to her!! I don't ask her to help with any projects, or bother her about the wedding cuz I know she doesn't give a crap.  Also we work together at our family's business and I see her everyday at work.  She's really pissing me of sitting at her desk right now!!!!