Modeling real world data in your computer system is going to be a pain.
It can either be a persistent, annoying upfront tax.
Or it can be kicking the can down the road until it stochastically explodes in your face in the future or becomes ever-more viscous quicksand.
It's easy to get started sketching stuff out in a spreadsheet, but it's hard to make it predictable, testable, and orderly.
The more you invest in the spreadsheet, the more unwieldy it gets.
The more you invest in a database, the more orderly it gets.