Why does the character on level 1 has 100 health when he supposed to have 50?

I have made a script for my RPG game were it changes the health of the player according to the level of the player. It works, but there's a problem. When a player is in level 1, the player has 100 health, when he supposed to have 50. It only fixes itself when the player resets. What did i made wrong here?

---------------
--[Variables]--
---------------
local player = script.Parent.Parent
local stats = player:WaitForChild("leaderstats")
local lvl = stats:WaitForChild("Lvl")

---------------
--[Functions]--
---------------

--Change health when a character is added according to the players leve
player.CharacterAdded:connect(function()
	repeat wait() until lvl
	if lvl.Value == 1 then 
		player.Character.Humanoid.MaxHealth = 50
		player.Character.Humanoid.Health = 50
	else
		player.Character.Humanoid.MaxHealth = lvl.Value*50
		player.Character.Humanoid.Health = lvl.Value*50
	end
end)

--Change health when the player levels up according to the level
lvl.Changed:connect(function ()
	repeat wait() until stats 
	if player.Character ~= nil then
		if player.Character:findFirstChild("Humanoid") then
			player.Character.Humanoid.MaxHealth = lvl.Value*50
			player.Character.Humanoid.Health = lvl.Value*50
		end
	end
end)

repeat wait() until lvl

and

repeat wait() until stats 

Do nothing!

Also on line 27, you should check if FindFirstChild returns nil.

Additionally, you only need to increase the character's health while they are alive, while they are alive! That may sound redundant, but I am trying to make you understand you can put that connect function inside of the other one.

---------------
--[Variables]--
---------------
repeat wait() until game.Players.LocalPlayer;
local player = game.Players.LocalPlayer
local stats = player:WaitForChild("leaderstats")
local lvl = stats:WaitForChild("Lvl")

---------------
--[Functions]--
---------------

-- Change health when a character is added according to the players level
player.CharacterAdded:connect(function(Character)
    if lvl.Value == 1 then
        Character.Humanoid.MaxHealth = 50
        Character.Humanoid.Health = 50
    else
        Character.Humanoid.MaxHealth = lvl.Value * 50
        Character.Humanoid.Health = lvl.Value * 50
    end

    -- Change health when the player levels up according to the level
    lvl.Changed:connect(function ()
        
        player.Character.Humanoid.MaxHealth = lvl.Value * 50

        player.Character.Humanoid.Health = lvl.Value * 50
        
    end)

end)

Also, correct me if I am wrong, but you don't need to create a separate check for making their health 50 if they are level 1, because their health is supposed to be 50 * level anyway?

---------------
--[Variables]--
---------------
repeat wait() until game.Players.LocalPlayer;
local player = game.Players.LocalPlayer
local stats = player:WaitForChild("leaderstats")
local lvl = stats:WaitForChild("Lvl")

---------------
--[Functions]--
---------------

-- Change health when a character is added according to the players level
player.CharacterAdded:connect(function(Character) 
    
    -- When the player spawns, change their health to 50 times their level

    Character.Humanoid.MaxHealth = lvl.Value * 50

    Character.Humanoid.Health = lvl.Value * 50

        
    lvl.Changed:connect(function ()

        --When the player levels up, increase their maxhealth and heal them fully

        player.Character.Humanoid.MaxHealth = lvl.Value * 50

        player.Character.Humanoid.Health = lvl.Value * 50

        
        
    end)

end)

EDIT Assuming you have ResetGuiOnSpawn Enabled, you don't need to connect when a new character is added.

---------------
--[Variables]--
---------------
repeat wait() until game.Players.LocalPlayer;
local player = game.Players.LocalPlayer
local stats = player:WaitForChild("leaderstats")
local lvl = stats:WaitForChild("Lvl")

---------------
--[Functions]--
---------------

    
    -- When the player spawns, change their health to 50 times their level

    Character.Humanoid.MaxHealth = lvl.Value * 50

    Character.Humanoid.Health = lvl.Value * 50

        
    lvl.Changed:connect(function ()

        --When the player levels up, increase their maxhealth and heal them fully

        player.Character.Humanoid.MaxHealth = lvl.Value * 50

        player.Character.Humanoid.Health = lvl.Value * 50

        
        
    end)