I think this decision is difficult because it depends on a variable you cannot control: the roommate (s). The questionnaires and other input can influence it. But there is no way to know, for instance, if the roommate is the sort of person who will ask your kid to go to meals together, which is the kind of awkward thing that is difficult in early freshman year.
A suite with separate rooms is ideal but apparently not available. Not only for the obvious combination of privacy and community, but because early on belonging to a group is easier than negotiating a relationship with one roommate.
Be careful to investigate limits on choices that result from asking for a single room. For instance, one of mine got a single room but it was in a building far from the rest of the freshman campus, because that was the only dorm with singles. The inclusion in STEM housing would be more important than getting a single, for instance.
There can be speculative gossip about why someone has a single so be aware of that. A student in a single can feel left out, too.
I think many kids with special needs want so badly to be “normal” (whatever that means) and starting off with a single announces they are not, so there is a lot of resistance. I found that my kid with clear medical issues was not embarrassed, but my kid with ADHD and psych, issues was mortified and quickly moved from a single to a double to feel- and appear- like everyone else. (Many kids refuse accommodations altogether due to this same drive to be “like everyone else.”)
I would let your daughter decide. This honoring of autonomy signals a new phase that will continue and expand. The main thing is, nothing is written in stone. If there IS a real problem, it is often fixable (you could find out what remedies might be available) and it really is a learning experience. By junior year there will be a satisfactory residential experience due to lessons learned!!
Sleep is a priority for everyone, and a darn good reason for a single. Ability to work in the room, if the library isn’t close or if that is where she prefers to work. Boy or girlfriends are a big problem and require self-advocacy. Otherwise I think it is worth it to try a shared room if that is what she really wants.
My kids did all the different options over the course of 4 years and it really did depend on the other person or people involved in the housing situation. It’s a gamble for everyone!
ps to CoyoteMom: ADHD is an adequate diagnosis for a single; just get a letter from a professional requesting this and other accommodations (you can write it yourself and have him or her sign it)