Long time lurker but first time poster.
DH has a 7yo DD from a previous relationship. She's with us every other week. We have a 2yo DD together and are expecting twin boys. We live in a 4 bedroom house, all 4 are double rooms. Smallest 2 are identical in size. Currently 2yo is in one of the "small" rooms and 7yo is in the larger one, with me and DH in the master. I think 7yo should be in the other "small" one (but as I said, it's not actually that small) and the twins should be in the bigger room since there will be 2 of them, and they'll be living here all the time. DH thinks the twins should have the smaller room since they're younger. Just to avoid drip feeding, twins will be in our room for around 6 months but I want to sort out bedrooms before we have 2 newborns in the house. Also won't be moving any time soon so would rather have a long term solution now.
YANBU - twins should have the bigger room
YABU - twins should have the smaller room