My little sister is two years younger than me and my MOH. She's single (this is relevent). When FI and I got engaged, I mentioned to her that we were going to do red dresses and autumn-colored flowers. She mentioned that she was thinking about doing red dresses too, when she got married SOMEDAY, but didn't go into it any further. She didn't act upset.A few months later, when we were looking at dresses, she found a short red dress that she LOVED and fit her perfectly. It was on sale so my mom bought it for her as her MOH dress. And everyone's happy, right?Fast forward to a few weeks ago. She gets pissed at me because I'm "stealing" her color scheme. She's mad about the flowers we picked out, she's mad because (even though we haven't picked out dresses yet and won't for awhile) I'm still going ahead and letting my girls pick red dresses of their choice. I offered to switch the color scheme (since she's the only one who has a dress) and she said no. But she continues to be passive-aggressive about it. Worse, she tells me that I'm spineless and that I'm letting FI (who was set on the red) "bully" me into "stealing" her color scheme.I'm upset because if she had mentioned to me how much it upset her months ago, I would have scrapped the red and gone with something else. Now she refuses to stop being passive-aggressive about it, but she also doesn't want to give up her red dress in favor of something else (even though I offered to pay for a new MOH dress for her in an alternate color). FI is pissed because she's making me upset, and because she's all upset about it when she's not even getting married any time in the foreseeable future. I don't know who is being a jerk, me or her. Advice? Any way I can compromise and make things better with her?

Books read in 2012: 21/50