Why wont it print "Test" when value is changed?

Running an event in a function will possibly not make that event work unless you are calling the function in a while true do loop... all you need to do is re-arrange the event and make y a global variable

Look:

local plr = game.Players.LocalPlayer
local pg = plr:WaitForChild("PlayerGui")

function gameo()
-- Objects

local Life = Instance.new("ScreenGui")
local onelife = Instance.new("ImageLabel")
local secondlife = Instance.new("ImageLabel")
local thirdlife = Instance.new("ImageLabel")
local lifecount = Instance.new("TextLabel")
y = Instance.new("NumberValue")  -- I MADE Y GLOBAL, I REMOVED LOCAL

-- Properties

Life.Name = "Life"
Life.Parent = game.StarterGui

y.Name = "count"
y.Parent = lifecount

onelife.Name = "onelife"
onelife.Parent = Life
onelife.BackgroundColor3 = Color3.new(1, 1, 1)
onelife.BackgroundTransparency = 1
onelife.Position = UDim2.new(0.551270008, 0, 0, 0)
onelife.Size = UDim2.new(0.0705550313, 0, 0.0990415365, 0)
onelife.Image = "rbxassetid://590924431"

secondlife.Name = "secondlife"
secondlife.Parent = Life
secondlife.BackgroundColor3 = Color3.new(1, 1, 1)
secondlife.BackgroundTransparency = 1
secondlife.Position = UDim2.new(0.621825039, 0, -0.00159744406, 0)
secondlife.Size = UDim2.new(0.0705550313, 0, 0.0990415365, 0)
secondlife.Image = "rbxassetid://590924431"

thirdlife.Name = "thirdlife"
thirdlife.Parent = Life
thirdlife.BackgroundColor3 = Color3.new(1, 1, 1)
thirdlife.BackgroundTransparency = 1
thirdlife.Position = UDim2.new(0.692380071, 0, -0.00159744406, 0)
thirdlife.Size = UDim2.new(0.0705550313, 0, 0.0990415365, 0)
thirdlife.Image = "rbxassetid://590924431"

lifecount.Name = "lifecount"
lifecount.Parent = Life
lifecount.BackgroundColor3 = Color3.new(1, 1, 1)
lifecount.BackgroundTransparency = 1
lifecount.Position = UDim2.new(0.762935102, 0, 0.00958466437, 0)
lifecount.Size = UDim2.new(0, 65, 0, 50)
lifecount.Font = Enum.Font.Arcade
lifecount.Text = "x3"
lifecount.TextColor3 = Color3.new(1, 1, 1)
lifecount.TextScaled = true
lifecount.TextSize = 14
lifecount.TextWrapped = true
y.Value = 3

lifecount.Text = y.Value


-- THIS IS WHERE THE ORIGINAL CHANGED FUNCTION WAS

end

gameo()
y.Changed:Connect(function()
    print("Test")
end) -- NOW ITS HERE!!! 

So this should print y... If it doesn't, it is probably because the code above wasn't thoroughly checked by me!

If this worked, accept and upvote please Thank you

ps: I also recommend using less global variables..