Editing text for textbutton doesn't show on the part, how do I fix this problem?

So I just started learning code, and I thought it would be fun to make a racing traffic light. So I did, the traffic light works perfectly fine, but the textbutton (in surfaceGUI) doesn't change and sometimes doesn't show up. How do I fix this/what did I do wrong?

local textbuttonText = game.Workspace.SurfaceGui.TextButton.Text

while true do
	game.Workspace.Part2.BrickColor = BrickColor.new("Really black")
	game.Workspace.Part1.BrickColor = BrickColor.new("Really red")
	textbuttonText = "Ready?"
	wait(3)
	game.Workspace.Part1.BrickColor = BrickColor.new("Really black")
	game.Workspace.Part3.BrickColor = BrickColor.new("Neon orange")
	textbuttonText = "Set?"
	wait(3)
	game.Workspace.Part3.BrickColor = BrickColor.new("Really black")
	game.Workspace.Part2.BrickColor = BrickColor.new("Bright green")
	textbuttonText = "Go!"
	wait(3)
	
end

local textbutton = workspace.SurfaceGui.TextButton -- using "workspace" instead of "game.Workspace" is much faster on typing time and slightly faster on indexing time

local p1 = workspace.Part1 local p2 = workspace.Part2 local p3 = workspace.Part3 -- index your parts before continuing with the script to save time, in some rare cases you will not need to do this (usually anti exploit or remaking an instance)

local waittime = 3 -- if you are using the same wait time for all three of the waits, create a variable so it is easier to edit

while true do
    textbutton.Visible = true -- if it is not showing up you may have an issue in another script or a different part of the code you are not showing me, fix it or use this to guarantee it shows up
    p2.BrickColor = BrickColor.new("Really black")
    p1.BrickColor = BrickColor.new("Really red")
    textbutton.Text = "Ready?"
    wait(waittime)
    p1.BrickColor = BrickColor.new("Really black")
    p3.BrickColor = BrickColor.new("Neon orange")
    ttextbutton.Text = "Set?"
    wait(waittime)
    p3.BrickColor = BrickColor.new("Really black")
    p2.BrickColor = BrickColor.new("Bright green")
    textbutton.Text = "Go!"
    wait(waittime)
end