AITA for not letting my miracle baby niece be my flower girl at my wedding?

I always wanted to be a bride. I get married in a month and it’s everything I’ve always wanted down to the last detail. My mom and I have been planning it since I was 10. <br><br>My sister and BiL struggled to conceive for 4 years. After many attempts, they finally adopted a baby girl this June. They’re obsessed with her and she’s so cute. I’ve always loved my sister and she’s my maid of honor.<br><br>The problem is that she and my BiL asked me if my niece could be my flower girl. I said no because I already chose my own flower girl. It was my other sisters daughter who is two and she’s been excited for a year. <br><br>My sister then asked if my other niece could also be a flower girl but I also already chose two other girls for that and they’re both two as well. It wouldn’t be fair to let one two year old do it and not the others. Plus, my nieces are only 6 months.<br><br>My sister asked me why I didn’t want her baby to be a part of my wedding and I said it’s because she’s only 6 months. The other girls I chose are already walking and can do the job easily. She then said her baby is a miracle and that she’d be perfect for the part since she’s so special. I said she is special, but she’s not physically capable of being a flower girl.<br><br>She then said okay fine, but I can bring her to the reception and I said yes. <br><br>I thought that was it, but apparently she went to complain to our mom because mom called me and said she was so disappointed I wouldn’t let my niece be my flower girl. I explained to my mom all of what I said above and she said I should just let her because she’s special and it would make my sister happy. I said I already chose my flower girl and I can’t just let one miracle baby be a flower girl over the others. <br><br>My mom then told me I’m selfish and I’m going to ruin my relationship with my sister. I said I’m not and I thought we already agreed on this until she went to complain to mom. My other sister also called me and said I should just let her be a flower girl. I’m so annoyed and it’s non stop. <br><br>AITA?