Starting investments before the start date of your business… is that allowed?

I started my sole proprietor (as a secondary occupation) on 1 October 2023.
Since then, I have made a number of investments and recorded them in Dexxter.
Now I would like to contribute a larger portion of these costs this year, but I want to keep my depreciations at 5 years.

I know that you can set the start date of the investment earlier.
But can this ‘earlier’ date also be a date before your start-up… for example, 1 January 2023?