Is it random or do they try to match you based on your interests
Should you really be worrying about that as a sophomore who hasn’t even taken SATs and many APs yet, let alone applied to and gotten into Cornell? I’m sure you can Google that stuff and it should tell you.
I think you can find your own if you want. I don’t see the problem of wanting to know more about a college this student is interested in, regardless of how ready he is to apply.
Current junior here. Upon getting accepted and accepting your place in the university, you’ll eventually have to take the roommate survey. It’s basically a way to try and match you with someone who has similar habits and room needs as you (noise level, mess level, stuff like that). If you meet someone who’s going who you’d like to room with, you can of course circumvent that. There’s an area on the survey where you can input someone’s ID (which is unique to that website, they don’t use your netID for whatever reason), and that person will be able to accept your request to be their roommate. When people get accepted, there’s always a Facebook group made for newly accepted students where everyone posts about themselves and tries to make friends before getting to Ithaca, a lot of that is to find a roommate because not a lot of freshmen get single rooms.