Hi Elif,
I am John J.D., a fellow Microsoft user like you.
I understand your concern. Unfortunately, Windows doesn't provide a direct way to check the activation date of your device. However, you can estimate it by looking at the "Original Install Date" in Command Prompt. Here's how:
> Open Command Prompt as an administrator.
> Type systeminfo and press Enter.
> Look for the "Original Install Date" field.
This date should give you an idea of when your Windows operating system was first installed. Keep in mind that this assumes the OS has only been installed once.
Hope this helps!
John J.D.