How do I fix a frame going visible randomly?

I am having a problem with a frame changing visibility randomly. For making a game Menu, I want the frame to be invisible when the game launches.

I have done some testing and realized that when I close the game with the frame open(visible), it appears invisible(how it's supposed to be) and if I close the game with the frame closed(invisible), it appears visible at the start of the game.

local Button = script.Parent
local Frame = script.Parent.Parent.Frame

Frame.Visible = false

function onClick()
    if Frame.Visible == true then
        Frame.Visible = false
    elseif Frame.Visible == false then
        Frame.Visible = true
    end
end
Button.MouseButton1Click:Connect(onClick)
while true do
    onClick()
end

I have no idea how to fix this, and it's bothering me very much. If you have a solution, I would be grateful if you would share it with me, thanks in advance.