How to make TextButton stop displaying 0?

I'm creating a code that will check your reaction speed. If you click the button a for loop will stop and tell your reaction speed, but when I click it and no matter how much time I wait, it still just displays 0. Is there any way to fix this?

The code is in a LocalScript in the TextButton.

Code:

wait(2)
print("ready to go")
local playergui = game.Players.LocalPlayer.PlayerGui
local TextButton = playergui.ScreenGui.TextButton
local randomtime = math.random(2,4)

wait(randomtime)

TextButton.BackgroundColor3 = Color3.new(0,225,0)
TextButton.Text = "Click!"

TextButton.Activated:Connect(function(activated)
	for i = 0, math.huge, 1 do
		wait()
		if activated then
			TextButton.Text = (i)
			break
		end
	end
end)

You should start your loop outside of function, because your loop starts only after a click. Better yet, do not use loop and use tick().

wait(2)
print("ready to go")
local playergui = game.Players.LocalPlayer.PlayerGui
local TextButton = playergui.ScreenGui.TextButton
local randomtime = math.random(2,4)

wait(randomtime)

TextButton.BackgroundColor3 = Color3.new(0,225,0)
TextButton.Text = "Click!"

--start loop here
local i
local clicked = false
for i = 0, math.huge, 1 do
	wait()
	if clicked then
		break
	end
end

TextButton.Activated:Connect(function()
	clicked = true
        TextButton.Text = to.string(i)
end)

However it is best to use tick() for this task. Google tick() for more info, but the short story is that you can get an accurate time difference thanks to it.

wait(2)
print("ready to go")
local playergui = game.Players.LocalPlayer.PlayerGui
local TextButton = playergui.ScreenGui.TextButton
local randomtime = math.random(2,4)

wait(randomtime)

TextButton.BackgroundColor3 = Color3.new(0,225,0)
TextButton.Text = "Click!"

local startTick = tick()

TextButton.Activated:Connect(function()
        TextButton.Text = string.format(".2%f",tick() - startTick)
end)