GUI leaderboard doesn't update player list correctly? (helppppppp)

Okay so i'm pretty sure it has something to do with my upd function

I've made a leaderboard and it works okay but the only problem I have is only players who join after you join appear. So basically it isn't showing players that were in the game before hand it only shows players that join after you. Here's my PlayerAdded script - this goes in the workspace

game.Players.PlayerAdded:connect(function(plr)
    wait()
    playerlist = Instance.new("StringValue", game.Workspace.Players) --This is where the player names are stored
    playerlist.Name = plr.Name
    playerlist.Value = plr.Name
end)

game.Players.PlayerRemoving:connect(function(plr2)
    if game.Workspace.Players:FindFirstChild(plr2.Name) then
        game.Workspace.Players[plr2.Name]:remove()
    end
end)

And here is the script that creates the leaderboard - this goes in my screengui in a frame called "Menu"

Main = script.Parent.Menu
PL = Main.PlayerList
pos = 0

game.Workspace.Players.ChildAdded:connect(function(plr)

function upd()
    getall = PL:GetChildren()

    for i = 1, #getall do
        getall[i].Position = UDim2.new(0, 0, 0, pos)
        pos = pos + 60
    end
    pos = 0
end

    wait()
    Frm = Instance.new("Frame", PL)
    Frm.Name = plr.Name
    Frm.Size = UDim2.new(1, 0, 0, 50)
    Frm.Position = UDim2.new(0, 0, 0, 0)
    Frm.BorderSizePixel = 0
    Frm.BackgroundColor3 = Color3.fromRGB(85, 85, 127)

    IL = Instance.new("ImageLabel", Frm)
    IL.Name = plr.Name
    IL.Image = "https://www.roblox.com/Thumbs/Avatar.ashx?x=100&y=100&username=" ..plr.Name
    IL.Size = UDim2.new(0, 50, 0, 50)
    IL.Position = UDim2.new(1, -60, 0, 0)
    IL.BackgroundTransparency = 1
    IL.BorderSizePixel = 0

    TL = Instance.new("TextLabel", Frm)
    TL.Name = "Name"
    TL.Text = plr.Name
    TL.Size = UDim2.new(1, -100, 0, 50)
    TL.Position = UDim2.new(0, 50, 0, 0)
    TL.FontSize = "Size28"
    TL.Font = "SourceSansLight" 
    TL.BackgroundTransparency = 1
    TL.BorderSizePixel = 0
    TL.TextColor3 = Color3.fromRGB(255, 255, 255)

    LVL = Instance.new("TextLabel", Frm)
    LVL.Name = "Level"
    LVL.Text = "0"
    LVL.Size = UDim2.new(0, 50, 0, 50)
    LVL.Position = UDim2.new(0, 0, 0, 1)
    LVL.FontSize = "Size28"
    LVL.Font = "Arial"
    LVL.BackgroundTransparency = 1
    LVL.BorderSizePixel = 0
    LVL.TextColor3 = Color3.fromRGB(255, 255, 255)

    upd()       

end)


game.Workspace.Players.ChildRemoved:connect(function(plr2)
    if PL:FindFirstChild(plr2.Name) then
        PL[plr2.Name]:remove()
        upd()
    end
end)