How do you change a players speed from a GUI?

So, I'm trying to make a GUI that can alter the player's humanoid speed. I am using a Text Box to get the speed but it just says that I am comparing a number with a string. I'm quite confused on how to make this work! Any help is appreciated!

local player = game.Players.LocalPlayer.Name

script.Parent.submit.MouseButton1Click:Connect(function()
	local body = game.Workspace:FindFirstChild(player)
	local humanoid = body:FindFirstChild("Humanoid")
	if script.Parent.enterSpeed.Text >= 30 then
		if humanoid~=nil then
			local speed = script.Parent.enterSpeed.Text
			humanoid.WalkSpeed = speed
		end
	end
end)

https://gyazo.com/5a82c427c10cacf71ffa03cf3b0fe39f