Attorney Andrew Branca says "Carry a gun so you're hard to kill, know the law so you're hard to convict." https://lawofselfdefense.com/ I also advise students to know the law so they can stay well within the boundaries of the law.
In the law in general, there are terms of legal art that are not English. Yes, the statute is written using English words and phrasing, but the statute is written in Lawyer, not English. I like to remind students that, while it is important to read the statute, we do not really know what the statute means until someone is arrested, convicted, and appeals the conviction. The resulting decision by the appeals court creates case law. And then there are jury instructions which attempt to state the law in plain English. However, the judge will decide which jury instructions the jury will receive, usually in consultation with the prosecution and the defense.
One of the legal terms of art in Texas law is "defense to prosecution." This phrase can vary in meaning depending on the jurisdiction. What it is NOT is a Mulligan. "Defense to prosecution" does not prevent arrest or prosecution. https://statutes.capitol.texas.gov/docs/PE/htm/PE.2.htm
A good way to get an understanding of Texas law is to discuss it with Texas lawyers. I have discussed this at length with Texas lawyers in my legal services program. They have a new YouTube channel. https://www.youtube.com/c/ArmedAttorneysTexas Penal Code Sec. 2.03. DEFENSE. (a) A defense to prosecution for an offense in this code is so labeled by the phrase: "It is a defense to prosecution . . . ."
(b) The prosecuting attorney is not required to negate the existence of a defense in the accusation charging commission of the offense.
(c) The issue of the existence of a defense is not submitted to the jury unless evidence is admitted supporting the defense.
(d) If the issue of the existence of a defense is submitted to the jury, the court shall charge that a reasonable doubt on the issue requires that the defendant be acquitted.
(e) A ground of defense in a penal law that is not plainly labeled in accordance with this chapter has the procedural and evidentiary consequences of a defense.
A good way to get an understanding of self defense law in general is Branca's Law of Self Defense. https://lawofselfdefense.com/shop-losd/ Another is Massad Ayoob's MAG20 Lecture. https://massadayoobgroup.com/ I've taken both of these and can recommend them highly.
I'm going back to resting, now.