Wow, culture clash. I shared with my "opposite" sex sibling until we were 8 and 6. People would have laughed at the idea that we couldn't share a room.

Everyone in my country that I know of that had three kids and only two rooms have always let the older kid have a room of their own and they younger kids have shared. No matter of gender.

That that would be child neglect is just beyond me.

When my friends little brother and sister wanted separate rooms (no they did not pair up the 14 year old girl and the 9 year old girl leaving the 7 year old boy alone, they let the kids close in age share), the parents decided to give up their bedroom.

I would have gone nuts sharing rooms after age 10 especially if a 6 year old sibling got their own room.