How long does an Apple order take to process?

It is normal to stay in the Processing stage until about a day before it ships. The shipping estimates are usually pretty accurate although I have sometimes received items a little earlier than the estimate.

Also see the following for information about order status: Viewing & Changing Orders - Shopping Help - Apple

It will arrive August 30 to September 1 as you've been told. "Processing" means it has not yet been manufactured and delivered to shipping.

MacBook Pros are not pulled from a warehouse. They are built to your order in a factory in China, and air-shipped to your country, then delivered by expedited local carriers.