Well, from marshmallow, Google made it mandatory for manufacturers to encrypt their devices. So if you haven't tinkered with your device (Unlocked the bootloader or flashed a new Rom), then it should be still encrypted.
Does TWRP request a password to access your files? Can you access your files from TWRP recovery without any kind of pin or passwords? If so, then your device is most likely not encrypted. And If you flash the Xiaomi.eu Rom, your device will still stay unencrypted. Though you can again encrypt it from settings, but every time you'd need to update your device, you'll need to decrypt again. So unless you run stock global without any tinkering, then you're better off with an unencrypted device.