Text Label Background Transparency not changing?

This script is mostly a test of trying to use most of the script I know. I created a function which would activate a screen (Text Label) when a certain player joins as well as audio

The way I did this was by having a Text Label present on the screen at all times but fully transparent and when the certain player joins it triggers a gradient of decreasing transparency of the Text Label background and the actual text. The screen will then disappear after 3 seconds of being at it's least transparent.

When playing the game though, the transparencies don't seem to change at all. I've tested the same script but using transparencies of parts and they've worked exactly how I wanted but whenever I use this script on the Text Label, it just doesn't work.

...Any Ideas?

-- Ava is the name of the ScreenGui

function screen()
	game.Workspace.TrueLove.Playing = true
	for i = 1,0.39,-0.01 do
		game.StarterGui.Ava.TextLabel.BackgroundTransparency = i
		game.StarterGui.Ava.TextLabel.TextTransparency = i
		game.Workspace.TrueLove.Volume = 1-i
		print(i)
		wait(0.001)
	end  
	wait (3)
	game.StarterGui.Ava.TextLabel.BackgroundTransparency = 1
	game.StarterGui.Ava.TextLabel.TextTransparency = 1
end

game.Players.PlayerAdded:Connect(function(player)
	if player.Name == ("moondragon333")
		then wait(2)
		screen()
	end
end)