Hi! I’m at Duke and I’d hazard the guess that it’s a similar lifestyle to Stanford. You can go to sleep whenever you want. Your neighbors will likely be quiet and if you have a room mate, they’ll probably respect your wishes.
A 12:30 (am) bedtime is earlier than I’d expect. People tend to stay up either working, going out or just hanging out with their friends. I’ve found that people in the states, especially at college, sleep later and wake later than we do at high school. Even going out, I was astonished to find that people will only start to party at 10pm (whereas in NZ this’d happen at 6pm) but you won’t hit the hay until 3am (whereas from what I remember you’d probably call it a night around midnight in NZ).
So be aware that your sleeping schedule may change and don’t worry if it does - there are still 24 hours in a day. Another thing I’d add is that your schedule may vary massively throughout the semester, mainly determined by midterms. In past semesters I’ve had three midterms within a week and spent the previous seven days/nights straight studying. The following week I’ve had no work and spend seven days/nights answering Q&A at ask.crimsoneducation.org