When I was growing up, until I was a senior in high school (at least I think it was my senior year) I shared a room with my sister. In fact, it wasn't until I was in 9th grade that I even got my own bed. We shared a bed for all those years.
This is the bed, and the girls are my granddaughters, Grace and Annie. They now share that bed. Anyway, my sister and I shared a room until I was 18.
There was a room next to our room (in the attic) which WAS the attic -- that's what we called it. It was unheated, and it stored all those things that didn't make it to the basement. I nagged and nagged and promised to clean out the room all by myself, if only mom and dad would let me have the room to myself. They acquiesced, finally, and I cleared it out. Put my bed in there, my desk, and a chair.
Now there was no closet in that room, so I hung my clothes on hooks on the wall, and put a sign over that part of the room labeled "Judi's closet". There was also a clothes rack (with clothing bags on it) which I tucked in one of the corners.
In order to allow some heat to come into that room, the door was taken off, and a curtain was put across the doorway which I opened up during the day and after I had changed for bed so that some heat would flow into the room. I had a big down quilt so in the winter I was quite warm. In the summer, of course, attics get very hot. Dad got a fan for the window and that drew out the heat during the day, then at night we'd reverse it and bring in the cooler air. I survived several years in that room, and the best part was that it was MY OWN. After I left, I think my brother took it over.
I do know, however, that whenever Alan and I came back home for a day or two we would have that room for ourselves -- he on a cot, me on my bed. Not exactly The Ritz, but it was home.