Acceptances sent at the same time?

[Grind12]

I was surfing the results section and noticed one person was accepted to one of my top choice programs. I have not heard back from this school. Do programs typically send their acceptances at the same time? Or does it vary among like a two or three week period? The person said they found out last week via e-mail, is it okay to contact the school and ask if I was accepted?

[abc123xtc]

It's not unusual for schools to send acceptances at different times (from what I gather). I would personally wait a week or two before sending an email.