I can tell you my experience.
I'm an only child. As part of my scholarship, I was required to live on campus. A friend from high school also got the scholarship, so we applied to live together. I got stuck in this NASTY dorm. We had 30 girls on one sideof the floor and 30 guys on the other side of the floor and one bathroom on each side. It was horrible. I'm sorry, but I just can't do bathroom business in such a public arena. I fully believe that one needs privacy when it comes to that. I had no problem showering there, but....c'mon....some things just require that you have one toilet and a door and some privacy.
Then, her boyfriend moved in. I had class from 8am-2pm and she had class from 2pm-6pm and he worked from 6am-2pm. See where this is going? I'd come back from class and he'd be naked and in her bed watching TV. I got to spend the entire afternoon alone with him. Big fun!
My neighbor next door was a chain smoker. I spent most of my time coughing.
There was no a/c, so it was unbearably hot on the 14th floor for part of the year.
I eventually moved to another dorm. It had 3 bathrooms - with doors. Life was good. The room was small. So small that 2 people couldn't stand up at the same time. But, my new roommate was cool. Then, the pot smoker moved in next door. I got a nice little high a few times a day. Again, no a/c and my roommate and I once took our blankets and slept outside.
Needless to say, I hated it. It just wasn't for me. At first, I felt guilty. Then I realized, there was nothing wrong with that. I just got used to certain comforts - like a bathroom that didn't involve 6 stalls and not having to inhale cigarette and/or pot smoke on a regular basis.
I think it's more about the dorm than the roommate. I actually didn't mind sharing the room - with the roommate, minus the boyfriend. I started college in 1994. I think dorms have come a long way since then. Have her go check out the dorms. If I had done that, I never would have agreed to live there. But, they didn't tell me where I'd be living, so I went into it completely blind.