Dash Mechanic Knows No Cooldown Help?

Okay so heres the brief explanation I made a dashing Script right but I cant seem to get it to function the way intended to so I want to make it have a cooldown script but its not working it either Only Dashes Once then completely breaks or if I remove the cooldown it'll just dash for infinitely I dont know what the issue...

local player = game.Players.LocalPlayer
repeat wait() until player.Character.Humanoid
local humanoid = player.Character.Humanoid
local mouse = player:GetMouse()
local cooldown = false

local anim = Instance.new("Animation")
anim.AnimationId = "http://www.roblox.com/asset/?id=04907165430" 

mouse.KeyDown:connect(function(key)
  if cooldown == true then return end
    if string.byte(key) == 113 then
      cooldown = true 
        local playAnim = humanoid:LoadAnimation(anim)
        playAnim:Play()
        script.Sound:Play()
        player.Character.HumanoidRootPart.Velocity = player.Character.HumanoidRootPart.CFrame.lookVector * 50
        wait(0.1) 
      cooldown = true
    end
    wait(0.5)
end)