Why doesnt this function fire when it shouldn't?

The code below should teleport the player from the hub-world, to a place inside of that game. However, I get the impression of that it fires before the player has clicked the button because of that it prints "ButtonClicked" before the player even gets a chance to press the button. Why does it work in the way it does?

local Player = game.Players.LocalPlayer
local TeleportService = game:GetService("TeleportService")


local function FirstOnClick()
    TeleportService:Teleport(Place1219Id,Player)
    print("ButtonClicked")
end

if TeleportationButtons.ScreenGui.First.MouseButton2Click then
    TeleportationButtons.ScreenGui.First.MouseButton2Click:Connect(FirstOnClick())
end