How to tell the ege of Computer

The model year reflects when the computer was introduced, not when it was built.

If you wish an easy way to see when it was built, get the free battery utility Coconut Battery:

https://www.coconut-flavour.com/coconutbattery/

In the image on that page you can see how it displays the date built.

The overview is accurate. Despite this being 2021, there is only one version of the 16” MacBook Pro, that being the 2019 model.

You received a new 2019 model/year computer.