One of the greatest pieces of advice that was given from my mentor, Jarett to me was always cutting losses quickly and your preparation for all phases in life. There's nothing in this world that is more valuable than your inner happiness and if you allow other influences to disrupt it for too long, then the fault is on you.
Also, you don't need to be the smartest person on the planet to live the life you want to have. One of the most the important reasons of whether you complete your goal or not is your preparation towards what you're striving for. Intellect helps, but that can only get you so far.