Gah! I decided to make a GUI thats purposly annoying at the begginging. Help??? [Solved it]

So The GUI's positions are purposly centered in the middle of the screen as soon as the first person joins. However, when I play they are always on the side of the screen, here Is my code...

for i,v in pairs(game.Players:GetChildren()) do
if v:IsA("Player") then
wait(1)
v.PlayerGui.MainText.Frame.TextLabel.Text = "Hi!"
wait(1)
v.PlayerGui.MainText.Frame.TextLabel.Text = "Wait, Hold on..."
wait(1)
v.PlayerGui.MainText.Frame.TextLabel.Size = UDim2.new{0, 1, 0, 1}
wait(3)
v.PlayerGui.MainText.Frame.TextLabel.Position = UDim2.new{.5, 0, .5, 0}
wait()
end
end

Note: This only after the Size and Position are executed by the script