Yep, it’s possible to integrate this into your current code.
I got the UNIX time of your event, you can make that a variable:
local eventUnixTime = 1577232000
Then subtract the EventTime and put it in a os.date:
local eventCountdown = os.date("!*t", eventUnixTime - os.time())
Finally, you can use all the different properties:
print(string.format("There's %d days till Xmas!", eventCountdown.day))
FYI: These variables and your EventTime variable should be defined inside the while loop, otherwise they never change!