Age is the final affirmative defense to a criminal act that is laid out in Chapter 8 of the Penal Code. In Texas, a juvenile is someone who has not yet reached the age of 17. While there are some exceptions, generally a person under 17 cannot be prosecuted for a criminal offense as an adult.
In Texas, before the age of 17, the State faces hurdles in prosecuting a person criminally instead of through the juvenile justice system.
Family Code, Sec. 54.02 provides:
The juvenile court may waive its exclusive original jurisdiction over a child who meets age/offense criteria if it finds, after a full investigation and hearing, that (1) there is probable cause to believe the child committed the offense alleged and (2) because of the offense’s seriousness or the child’s background the welfare of the community requires a transfer for criminal proceedings. The prehearing investigation must include a diagnostic study, a social evaluation, and an investigation of the child, his circumstances, and the circumstances surrounding the offense. The law recites various factors that must be considered in making the transfer determination. If the court transfers (or retains) jurisdiction over one offense, it must likewise transfer (or retain) jurisdiction over all others arising out of the same criminal transaction. Once the juvenile court transfers jurisdiction of a case, the adult criminal court may not remand it.
Also note that once a person has been transferred to the criminal justice system, they will generally be back in the criminal justice system, and not the juvenile justice system, after any felony arrest, regardless of age.
Family Code, Sections 54.02(m) and (n) provide:
If a child has previously been transferred to adult court, the juvenile court must waive jurisdiction over any subsequent felony offense, without the elaborate investigation required in connection with discretionary waivers, unless the child was acquitted or not indicted, won a dismissal with prejudice, or had his conviction reversed on a final appeal in the previous case.
Penal Code Sec. 8.07 provides:
(a) A person may not be prosecuted for or convicted of any offense that the person committed when younger than 15 years of age except:
(1) perjury and aggravated perjury when it appears by proof that the person had sufficient discretion to understand the nature and obligation of an oath;
(2) a violation of a penal statute cognizable under Chapter 729, Transportation Code, except for conduct for which the person convicted may be sentenced to imprisonment or confinement in jail;
(3) a violation of a motor vehicle traffic ordinance of an incorporated city or town in this state;
(4) a misdemeanor punishable by fine only;
(5) a violation of a penal ordinance of a political subdivision;
(6) a violation of a penal statute that is, or is a lesser included offense of, a capital felony, an aggravated controlled substance felony, or a felony of the first degree for which the person is transferred to the court under Section 54.02, Family Code, for prosecution if the person committed the offense when 14 years of age or older; or
(7) a capital felony or an offense under Section 19.02 for which the person is transferred to the court under Section 54.02(j)(2)(A), Family Code.
(b) Unless the juvenile court waives jurisdiction under Section 54.02, Family Code, and certifies the individual for criminal prosecution or the juvenile court has previously waived jurisdiction under that section and certified the individual for criminal prosecution, a person may not be prosecuted for or convicted of any offense committed before reaching 17 years of age except an offense described by Subsections (a)(1)-(5).
(c) No person may, in any case, be punished by death for an offense committed while the person was younger than 18 years.
(d) Notwithstanding Subsection (a), a person may not be prosecuted for or convicted of an offense described by Subsection (a)(4) or (5) that the person committed when younger than 10 years of age.
(e) A person who is at least 10 years of age but younger than 15 years of age is presumed incapable of committing an offense described by Subsection (a)(4) or (5), other than an offense under a juvenile curfew ordinance or order. This presumption may be refuted if the prosecution proves to the court by a preponderance of the evidence that the actor had sufficient capacity to understand that the conduct engaged in was wrong at the time the conduct was engaged in. The prosecution is not required to prove that the actor at the time of engaging in the conduct knew that the act was a criminal offense or knew the legal consequences of the offense.