Which kids shold share a room?

52403bride

Hi. I have 2 stepkids - 14 year old girl and 11 year old boy.  I also have a 3 year old boy and a little girl on the way.  We need to have 2 of the kids share a room, as we do not have any extra rooms.  We converted the dining room downstairs into a bedroom for my stepdaughter when my son was born.  Should we have the 11 year old and 3 year old share a room?  That would give the baby her own room.  Or should we have the 2 little ones share a room?   My stepkids only sleep at our house 6 nights per month, so it makes more sense that the 11 year old and 3 year old share, but I don't know.  Help!