Trying to find birth certificate of my grandmother

My Granny Olive Victoria Supple-Grant met my grandfather when he was stationed in Australia during WW2. She came to the United States as an Australian war bride. I believe she was from Cowra. I would like to have her birth certificate. She passed when I was a small child and all her children have passed away including my grandfather.

I understand that Olive Victoria Grant (or maybe Sipple/Supple) was born < 100 years ago, so it is not freely available until late 1928(?).

If you don’t want to wait those 2 ½ years for that birth certificate to turn up, here are some links for you to look at:

Note:
You might want to acquire her Jan 1946 marriage certificate as a start.
Goto https://familyhistory.bdm.nsw.gov.au/lifelink/familyhistory/search
Set “Search by number only” to “Yes” and then Reg#: 6690/1946

FYI Australian BDM certificates are not cheap!