You can't necessarily prevent being incapacitated. However, you can make plans, just in case it should occur.
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 be incapacitated. It is not difficult, 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.
You will need a general durable power of attorney so someone else has the authority to handle your day-to-day finances. A medical power of attorney will allow someone else to make your health care decisions. A living will let you decide ahead of time what medical means can be taken to prolong your life.
An estate planning attorney can advise you on creating an estate plan that fits your unique circumstances now and preparing for possible circumstances in the future.
Reference: TC Palm (Feb. 20, 2018) "Be as prepared as you can by planning for incapacity."