Am i being unreasonable?

So I was supposed to be getting married in Mauritius on October 31st this year, but due to Covid it isn’t happening. Instead we are getting married in a church near where I grew up on the same date. My parents got married there and I was christened there so it has meaning for me. Originally we thought we could have 30 guests and then it got cut to 15. Fine, I dealt with that. So now my problem. I have 4 bridesmaids - two best friends, my sister and my fiancé’s sister. My fiancé’s sister doesn’t want the hairdresser to do her hair because her cousin is good at her - fine. I walked into my in laws house on Sunday and she’s having a hair trial with her cousin. Okay, didn’t know that was happening. They proceed to construct a messy bun hairstyle. It looked pretty but I had already decided that I want a messy bun and thought the bridesmaids could have their hair down. Me being me, I was too scared to say anything at the time so yesterday (Monday) I sent photos of the hair do to the bridesmaid group. Instantly my two friends said that if I was having my hair up then shouldn’t theirs be down - exactly! My sister also has shorter hair that won’t go up. So I play innocent and say that yes that would be a good idea. Then I send some down hairstyle photos to the group and they all loved them. Later in the day I get stroppy messages from my sister in law saying she wants her hair up and has done all along(?!) so how can I say I want them to have it down, is it just because my sister’s hair is short? She’s “disappointed” and as I’m so laid back about everything else, why do I care about hairstyles?! So because I’ve given them free choice over shoes, make up etc. now I can’t have an opinion on hair? I haven’t replied to her because I’m too upset and annoyed. My fiancé can’t really see what the fuss is about because he doesn’t care too much about hairstyles.
We aren’t having our dream beach wedding, it’s all changed and I just want to choose the bridesmaid hair, am I being unreasonable? Please let me know.