California Code, Probate Code - PROB § 8424

(a) If a person named as executor is under the age of majority and there is another person named as executor, the other person may be appointed and may administer the estate until the majority of the minor, who may then be appointed as coexecutor.

(b) If a person named as executor is under the age of majority and there is no other person named as executor, another person may be appointed as personal representative, but the court may revoke the appointment on the majority of the minor, who may then be appointed as executor.