There are no age requirements for disabling accidents or illnesses, so it would be wise for everyone to plan for what would happen if they were to become incapacitated, according to TC Palm in "Be as prepared as you can by planning for incapacity."
To get started, schedule an appointment with an estate planning attorney. The attorney can prepare the necessary documents for incapacity. Among other things, you may need a general durable power of attorney so someone else has the authority to handle your day-to-day finances, a health care power of attorney that will allow someone else to make your health care decisions, and a living will that will let you decide ahead of time what medical means can be taken to prolong your life.
An experienced estate planning attorney can advise you on creating an estate plan that fits your unique circumstances, which could include preparing for a future disability or incapacity.
Reference: TC Palm (Feb. 20, 2018) "Be as prepared as you can by planning for incapacity."