You can go your entire life never needing to defend yourself in a violent attack. But, do you have the training if you are attacked?
One of the biggest mistakes people make is getting instruction in the Law second-hand from someone who may not know themselves.
If you trust your life or the lives of your Family to your skills; you have a moral obligation to obtain competent instruction. It could genuinely mean the difference between walking away or not. If you would get educated before scuba diving or parachuting, both life-threatening activities; then you have no reason not to get the same level of instruction for self-defense.