This is so individual! I can fall asleep and stay asleep 'most anywhere, especially with a sound machine and after walking around all day, like at WDW. I've shared a bed with other adult women on church summer camp trips as chaperones, missions trips, fun girls' weekends, distant wedding weekends, work-related conferences... most of these were for ~4 nights with a couple for a week. We all knew about the arrangements ahead of time and agreed to the terms so that probably accounts for it going so well every time. Morning larks showered in the mornings, night owls showered in the evenings, anyone wanting a long shower/bath took theirs last, after everyone else was done... everyone respects one another's space and needs for quiet when in the room, taking conversation/phone calls out of the room during quiet hours. These things were discussed ahead of time and prevented misunderstandings later.
When I've travelled with my DD's family, I've shared a 2 full size beds with their 3 young kids. We all still got a good night's sleep, even with a wiggly little one next to me, ha, ha. My sister, OTOH, has always been a very light sleeper. She simply cannot get a good night's rest if she's sharing the same room with someone else who makes any noise at all. Even someone calmly walking down a hotel hallway or flushing a toilet in the room above or besides hers will disturb her sleep and then she lies awake for an hour or more afterward. Sharing a room at all is just truly not a reasonable plan for her.
It's your trip and you're planning to travel with other adults. So communicate your wants and needs with them. Give them a chance to think about it and respond. You may be surprised at what you all can come up with together, to please everyone.