Find a good class that will teach you not only how to handle a weapon, but about the legal aspects of what it means to carry and to kill someone. Find out what can and will happen to you and your family if you are ever in that situation. I had a very good CCW instructor who spent a good part of the class going over what will happen and what you need to understand. Even if you are in the right, it will disrupt your life for a very long time.
AMEN!!!!
I used to do research in a part of a law library where the title of a book on an adjacent shelf was "The Process is the Punishment", referring to the criminal justice system.
Even IF you have a good self defense claim, there is still a very good chance that you will be charged and have to prove that defense at trial. THAT is extremely expensive, and defense attorneys typically won't take an unsecured promissory note. So, there goes your house (or your parents'), just to pay for attorney fees necessary to prove you were in the right. During that defense, pretty much everything else in your life becomes secondary to that, and you're consumed with participating in that defense. Your relationships suffer, your work suffers (or you lose your job), your mental state suffers. And all that is assuming you have a righteous case and are acquitted.
If you are convicted, you have costs and attorneys fees for the appeal (usually just to get back to a second trial where you get to pay your attorney all over again for another trial). Then there's jail or worse, loss of income, loss of benefits for you and your family and loss of a big chunk of your life, not to mention the impact of the incident and the judicial proceedings on your mental and emotional health.
On top of all that, you'll likely be sued civilly for wrongful death or serious injury by the guy you shot or his heirs to get at every last dollar you have. It's not unusual for a pissed off family to pursue you through that process even if you don't have any money to satisfy a judgment -- just so they can pursue you for any dime you earn for the rest of your life out of a sense of retribution. All those consequences mentioned above all over again (except for jail), but the standard of proof civilly is only "a preponderance of evidence" as opposed to the criminal standard of "beyond a reasonable doubt", and the plaintiffs don't typically need the unanimous jury verdict a prosecutor does for a conviction in his criminal case.
So, in absolute agreement with vectorvp's post, UNLESS you are in a situation where it is obviously clear cut to almost anyone that you had NO alternative but shoot, shooting someone will effectively mean that your life is over as you knew it -- you will be stuck in legal hell and financially broken by it -- with terrible effect on your family too. And that's IF you don't also go to prison.
Best to stay the hell out of the legal system if at all possible, and that advice should be amplified about 100X when it comes to the criminal system. vectorvp's advice is stellar -- I've wondered if I would have reacted differently in the thug situation I posted about above (esp. at 23) if I'd had the .357 with me. Glad I never found out, because if you carry, you better have that boosted ego reflex completely under control -- can't say I did back then, and especially not in that humiliating victim setting those two assholes imposed on us.