Many people are under the mistaken impression that you should be older before you create an Advance Heath Care Directive. They think it's something "old people" do. The truth is you should consider creating one right after you turn 18 - no longer a minor in California.
When you become an adult, you are no longer a minor and therefore have the right to give instructions about your own health care. In fact, others (even parents) are not allowed to make decisions for you without such a legal document because they don't technically have the legal right to do so any longer. You may not always have the ability to make decisions about your own health care. If that becomes the case, a duly executed Advance Health Care Directive gives someone else the legal right to make health care decisions for you. It doesn’t matter how old you are; perhaps today you will become a victim of an accident that will put you in a coma. Who do you want to be making the decisions that will affect you for the rest of your life? With an Advance Health Care Directive, you would have the power to decide who makes crucial life or death decisions for you. Also, it's not simply about "pulling the plug" but more about designating a legal advocate. Notice, you don't have to be "old" to create one. Life doesn't discriminate when it comes to tragedy.
A Health Care Directive essentially allows you to give specific instructions about your health care and allows you to appoint a person to make health care decisions for you if you are unable to do so yourself. It allows this person, in the event you are unable to do so, to access your medical records (if it's done right) and gives them the power to make decisions about treatments, surgeries, services, or other decisions having to do with your health. You can appoint others if the first person you designated is not willing or available. The Health Care Directive is the ultimate tool to taking charge of your life and managing yourself. It legally records your health wishes to be enacted if you cannot act for yourself.
Now what happens if you don’t have an Advance Health Care Directive? Consider the well-known story of Terri Schiavo, a woman from Florida who didn’t have an Advance Health Care Directive. She collapsed at home, and the lack of oxygen she suffered from caused her to enter a vegetative state. Because there was no legal document/directive as to what her health wishes were, her husband and her parents fought for years about whether to keep her alive in her state or remove her life support. People generally think the spouse is in charge, but that is not the case. This event took its toll on all those involved, both emotionally and financially. An Advance Healthcare Directive would have solved this problem.
So whoever you are, young or old, 18 or 81, having an Advance Healthcare Directive is very important tool to have in your toolbox in case something occurs.