I don't want to wear the bridesmaid dress my sister (bride) has chosen for me because it will be 4 sizes too big.
For context, I have just had my first baby and am exclusively breastfeeding. My sister's wedding is in June and I am one of her four bridesmaids. The dress she has chosen is from a US based company and costs $70 to ship to the UK. Annoyingly she asked me to order it when I was still pregnant so I had to do my best guess when I was ordering in terms of sizing. I ordered the equivalent of a UK 16 thinking it would be roomy, because I usually wear a size 12/14 UK.
However, since giving birth my breasts are much much larger and when the dress arrived it was way too small around the bust area, despite fitting nicely on the rest of my body. It's so small around the bust that I can't do it up at the back by several inches so tailoring it seems highly unlikely.
The issue is my sister now wants me to order the same dress but in the size that will fit best around my boobs, which is a UK 22. I feel very strongly that this will be enormous on the rest of me, but she is convinced that I can get it tailored to fit.
I have found an almost identical dress from a UK website that offers custom tailoring so I can order with my exact measurements, however my sister has said no because she wants all the bridesmaids in the same dress from the same company.
My mum is saying she will pay for the dress my sister wants to avoid the drama, but I feel like just ordering the UK dress myself anyway because I know it will fit.
Am I being unreasonable for wanting to go to my sister's wedding in a dress that actually fits? At this point I feel like I would almost rather just not be a bridesmaid so I can feel comfortable in my postpartum body and not feel like I look ridiculous in a dress that is several sizes too big. What should I do in this situation?