That would depend on your reasoning for needing to sit at another centre e.g. kids who are overseas representing Australia in some team or other would be able to sit their HSC overseas but be entered with their own school (there is some paperwork involved in this and approval has to be given - I know because my school has had this happen).
Usually though you will sit at the same centre as your cohort.
If you are needing to (not wanting to but needing to do so) you would/should have already sought approval and have it rather than be thinking about it now.
The reason has to be very good though and not just "I don't won't to sit it with the kids I went through school with'.
At this stage your marks etc have been entered from your school so any moderation etc will only happen with that cohort as there is no other way to accurately use your marks so wherever you sit the exam you will be registered as coming from your school.
