Why my level up system is not working?

local lv = Instance.new("IntValue")
    lv.Parent = psts
    lv.Name = "Level"
    lv.Value = 1

local xp = Instance.new("IntValue")
    xp.Parent = psts
    xp.Name = "Exp"
    xp.Value = 0

local xpMax = Instance.new("IntValue")
    xpMax.Parent = psts
    xpMax.Name = "ExpGoal"
    xpMax.Value = 10

xp.Changed:Connect(function()
        if xp.Value >= xpMax.Value then
            lv.Value = lv.Value + 1
            xp.Value = 0
            xpMax.Value = xpMax.Value * 2
        end
    end)

i don't think i need to explain more, i just want to level up