@StaceyWoensdregt You can check it from any website like smallseotool and others on the Google search result page. Refer to the screenshot uploaded on Drive.
https://drive.google.com/file/d/1JuKbgBvfSG5GD8-aO_EgfL8Qh0Mxy8Cr/view?usp=sharing.

However, the age of a site refers to the time since when you purchased the domain you can simply check from your domain provider or hosting.

I think you want to check the DA PA of your website you can check from moz.com.

If you want a complete free audit for your website you can fill in and submit the details here:
https://easyswapp.com/free-seo-audit-for-your-website/