AITA for kicking my SiL out after she placed herself in my bridal party and then tried to wear a white dress to my wedding?

I (28F) got married last month, and it was everything I dreamed it would be. However, the entire experience was nearly ruined by my SiL. She's my husband's younger sister.<br><br>My SiL (25F) is a very sweet girl, and I get along with her quite well. She was single at the time, and I assumed she wouldn't have a date to my wedding, so I offered her a spot in my bridal party. She would've been one of my bridesmaids.<br><br>My SiL does have an odd sense of humor, and there were red flags that I ignored. She would occasionally joke that she's going to do this or do that. She told me she placed a bet with my husband that I'd forget about my own wedding. Her jokes can be a bit off, but they're always harmless. I figured it wouldn't be a big deal.<br><br>Fast forward to the day before the wedding. We were setting up at the venue with the wedding party, parents, and other family. My SiL was acting strange the entire day. At one point, she pulled my husband aside for a few minutes. I didn't think anything of it until he came to me, looking panicked.<br><br>He told me that my SiL asked him if she *had* to wear the dress we gave her, or if she could wear her own dress. He asked why, and she said that she wanted to match the wedding party theme. He asked what theme, and she started giggling. Apparently, she thought it would be funny to wear a white wedding dress at my wedding.<br><br>I felt like I'd been punched in the gut. In my entire life, I'd always dreamed of my wedding day. I'd spent months planning, and the last thing in the world I wanted was someone else wearing a wedding dress at my wedding. I asked my husband what he told her, and he said that he told her no.<br><br>We went looking for her, but she had already left. We were stressed that she might show up in a wedding dress the next day, so we decided to talk to her. We called her, but she wouldn't answer. We tried texting, but she ignored us.<br><br>I was panicked. We considered talking to her parents, but we decided to give her the benefit of the doubt. That night, we went to bed not knowing what she had planned.<br><br>The next morning came around, and we were setting up. The bridesmaids started showing up, including my SiL. We didn't want to ruin her day, so we played it cool and acted like nothing was wrong. My husband and I were panicking, because her dress was covered. We figured she'd see that other bridesmaids also had their dresses covered, and she wouldn't think anything of it.<br><br>My SiL had a big smile on her face, and she was giving us weird looks, constantly. She was acting strange, but we figured she was just messing with us. Once she changed into her dress, she came up and hugged me. I congratulated her on looking beautiful, but I was secretly worried.<br><br>When she had her back turned to me, I pulled up the photo that my husband took of the dresses. The photo was of all the dresses hung up next to each other, and it was clear that there was a *very* noticeable difference between the wedding dress and the bridesmaid dresses.<br><br>I realized then that I was being paranoid, and that SiL wasn't going to actually wear a wedding dress. It wasn't until later, at the reception, that I learned how wrong I was, and how right I actually had been. One of my bridesmaids came up to me and told me something that made my heart stop. Apparently, my SiL had shown up to the venue in a wedding dress.<br><br>One of my bridesmaids was there early, and she saw my SiL walking in with a huge wedding dress. The dress was covered, but you could see a wedding dress underneath. My bridesmaid was confused, and she asked my SiL if she was there for a photo shoot that was happening a few days after our wedding. My SiL said no, that she was actually in my bridal party.<br><br>My bridesmaid (and MOI) thought it was a joke, but my SiL said she wasn't laughing. My SiL gave a smirk and told my MOH, "Surprise!" My MOH asked if she was serious, and my SiL said of course she was. My MOH was shocked, and told my SiL that she couldn't wear that. My SiL asked why, and my MOH said that it was my wedding, not hers.<br><br>My SiL got angry. She told my MOH that she had the right to wear whatever she wanted, and that she was going to wear that dress no matter what. My MOH was worried, so she called my husband. He was busy working with the caterer, so she texted him. He didn't get the text for a few minutes, and apparently that was enough time for my SiL to get changed.<br><br>My SiL came into the dressing room a few minutes later, wearing the dress we gave her. She was acting strange, but she seemed calm. She didn't say much the rest of the day.<br><br>During the reception, my MOH came up to me and told me what had happened earlier that day. I couldn't believe it. I asked her to show me a photo of the dress my SiL was wearing, and she sent me a photo. I wanted to cry. My SiL was wearing a wedding dress with a full, flowing veil. It was a beautiful dress, and it would've been perfect at her own wedding one day.<br><br>As the reception went on, my SiL started drinking. She eventually got drunk, and she made a scene by telling everyone how I'm a "prick" and that I'm "selfish". She gave a toast that was supposed to be about me and my husband, but it ended up being about how childish I am.<br><br>The next day, my husband and I discussed what to do. We decided to uninvite her from our after party, which was happening a few weeks later. My SiL called us when she found out, and we told her that we didn't want her there after what she said and did.<br><br>She started yelling at us, and we hung up on her. She called back a few minutes later and apologized profusely. She begged us to let her come, and promised that she wouldn't drink. We told her no, and said we'd talk to her the day before the after party.<br><br>The next day, I sent her a text, inviting her to a fake bachelorette party. I told her that it was being held at a fancy restaurant, and that she would be the only person there other than me. I told her that we'd be going out for a night in the city afterwards.<br><br>She texted back and said that she'd love to go. I told her to meet me at the restaurant at 2pm, and she agreed.<br><br>On the day of the so-called "bachelorette party", I went to my SiL's house. I rang the doorbell, and she opened it. She was wearing jeans and a T-shirt, and she had sloppy makeup all over her face. She had just woken up, and had clearly been hungover.<br><br>I asked her where she was going, and she told me that she was meeting me at the restaurant. I asked why she was dressed up, and she told me that she was just "getting ready". I asked her to get her things, and she grabbed a duffel bag.<br><br>We got into my car and drove. She was silent the entire time, and I could see her starting to sober up. She started looking confused, and finally asked where we were going. I pulled into the parking lot of a local laundromat.<br><br>My SiL started screaming at me that this wasn't the restaurant, and that she wasn't going in there. I told her that I was giving her a lesson. I said that she wanted to embarrass me at my own wedding, and now it was time for her to get embarrassed. I told her to get her ass in the laundromat, because I wasn't leaving until she did.<br><br>She started crying and kicking, but eventually she got out of the car. I drove away and left her there.<br><br>My SiL has been angry with me ever since. I think what I did was justified, but some people disagree. AITA?<br><br>&#x200B;<br><br>EDIT: I also want to add that my husband and I were both *very* clear that we didn't want a theatrical wedding. We wanted a classic, simple, elegant ceremony, and that's exactly what we got. My SiL knew that, and she knew how much this wedding meant to me.<br><br>&#x200B;<br><br>EDIT 2: My SiL knew that we didn't want a theatrical wedding, and that was clear from the very beginning. She helps me with wedding planning, and she's heard me complaining about wedding venues, caterers, flower shops etc. etc. She knew how much money, time, and effort went into this wedding.<br><br>&#x200B;<br><br>EDIT 3: It was a Sunday morning when I dropped her off, and the laundromat was open. She stayed there for a few hours, and a few people came in while she was there. She kicked and screamed until someone called the police. They talked to her for a while, and eventually they took her home.