It depends on the school you're going to. As for cleanliness, this is totally dependent on your school. Mine has the bathrooms cleaned everyday (thank God, lol), and the rooms are spacious enough for two desks. The beds are pretty uncomfortable, but that can be remedied with a mattress pad.
As for the kids, well, it depends. You may get jerks who will mess with you, but you may also get some really nice people who will try to befriend you. I'd like to believe that people aren't so horrible as to go around messing with someone's service dogs, but people can be cruel. If anyone does anything to hurt you or your dogs, just report them to your RA. Maybe you can put in a request to transfer, too.
Don't worry too much about the age difference. I doubt anyone will even notice. Anyway, not all college kids are immature jerks. I'm a college freshman, and I think I'm pretty mature for my age. One of my high school teachers actually depended on me to keep his life in order. Well, not really his life. He was the advisor of this club I was president of, so I just took care of everything, and maybe graded some papers for his classes from time to time. Still, he said I was the most responsible of everyone and would usually come to me if he needed something done.
But back to answering your question. There are jerks everywhere, even my school where everyone I met at orientation seemed really nice. Kids will party and drink and be so annoying that you want to punch them in the face a few times, and maybe even throw a chair at them, lol. But there are also really nice kids who are quiet and studious and friendly.
If worse comes to worse, report the little brats to your RA and request a transfer, or even a private room. Schools sometimes grant private rooms to people for medical reasons. Since you have service dogs, you might get a room to yourself.
Good luck!