Family emergency derailed my Meta onsite prep. How bad is it to reschedule?

I have a Meta onsite in a few days, but a family emergency just derailed my prep and mental headspace. Does rescheduling hurt my chances or risk the headcount being filled before I can interview? I’d

I have a Meta onsite in a few days, but a family emergency just derailed my prep and mental headspace. Does rescheduling hurt my chances or risk the headcount being filled before I can interview? I’d rather push it back two weeks than fail and face a one-year cooldown, but I'm worried how it looks. To people who have been selected: is it common to reschedule?