As a result of the pandemic, the public has gotten used to planning to get goods in time for festivities. Plus, with these supply problems we are going through now, the public feels that retailers will not have adequate stock for Christmas. So the public has started its holiday shopping. Christmas products are now being brought early than usual, e.g. "gingerbread house" and "letter to Santa" kits.
The public is buying ahead.
As a result, major retailers are already starting their holiday programs.
I would suggest that you start too you have now about a month.
If the delivery service you use is Australia Post, you have less time as these are the cut-off dates.