The executor of your estate should be someone you trust to handle your estate just as you want it handled. You want to be certain that the executor will faithfully follow the instructions laid out in your will, including distributing your assets according to your wishes.
Many people trust one of their own children above all other potential candidates for this responsibility. They name that child as their executor, having put little thought into the consequences of doing so. It is not always a good idea, as Texas Lawyer discusses in "Mamas, Don't Let Your Babies Grow Up to be Executors."
Being an executor is not an easy job. If people do not know what they are doing, it is very easy for them to make mistakes. They can often be held personally liable for those mistakes.
An executor does more than just distribute the assets of the estate. He or she must be able to communicate with the court and with any heirs about the estate. If, for example, the executor and a sibling do not get along, there can be problems. In some cases, executors will need to invest assets for a period of time, before they can be distributed. The executors need to do that investing wisely.
Before naming one of your children to be the executor of your estate, think through whether it is a role you really want that child to have. It might be better, in some cases, to name a professional.
Reference: Texas Lawyer (March 6, 2018) "Mamas, Don't Let Your Babies Grow Up to be Executors."