Several reputable databases track global activation logs for Xiaomi devices.
If the official site is unavailable, you can use these secondary options: How To Check Xiaomi Phone Activation Date how to check activation date of xiaomi phone top
Since Xiaomi phones run Android, they register with Google the moment you sign in. This is a great backup if you can't access Xiaomi's specific tools. How to do it Log into your Google Account Manage all devices Select your Xiaomi phone to see the "First signed-in" : This only shows when Several reputable databases track global activation logs for