How can I get all players PlayerGui?

I want to make a script where if there are 2 or more players in the server, it will change the Gui's text at the top, and if there are less it will change it also, but whenever it gets to the line that changes the text, it returns nil. This is what I wrote:

NumOfPlayers = 2
gamewait = 10

while wait(2) do
	local topGui = game.Players:GetChildren('Player')
	wait(3)
	if game.Players.NumPlayers > NumOfPlayers then
		for i = 0, gamewait do -- 1
			topGui.PlayerGui.ScreenGui.TextLabel.Text = "Next Game Starts In:  " ..gamewait - i .." Seconds."
			print('1')
			wait(1)
		end
	else
		if topGui then -- 2
			topGui.PlayerGui.ScreenGui.TextLabel.Text = "There needs to be ".. NumOfPlayers - game.Players.NumPlayers .. " more player(s) to start the games."
			print('2') 
		else
			print('X-2')
		end
	end
end

Here's a better method! Make a numbervalue in workspace called "NumOfPlayers".

local numofplayers = game.Workspace.NumOfPlayers.Value
local enoughplayers = false

game.Players.PlayerAdded:connect(function()
numofplayers = numofplayers + 1
end)

game.Players.PlayerRemoving:connect(function()
numofplayers = numofplayers - 1
end)

while true do 
if numofplayers >= 2  then 
enoughplayers = true
else 
enoughplayers = false
end
end

After that, you should make the code that checks if enoughplayers is equal to true, then makes people start the game. You might want a boolvalue saying if the game has started. This will eliminate a code running over and over if enoughplayers = true.