1. Find a local shooting range WHERE THEY RENT GUNS!
2. I reccommend Magnum range, but they are in Upland, CA which is quite a drive if you are in LA.
3. Try a 9mm automatic, 45 ACP, 357 magnum and maybe a shotgun.
4. Decide what you are most comfortable with. The shop owner might be some help, but if you know someone who already has some guns to go with you even better.
5. Find your local Turners. www.turners.com
6. Goto turners and take the test for your California handgun card. 20 common sense questions such as:
When carrying your firearm in your vehicle it should be carried.
a) Loaded on the seat next to you.
b) Unloaded in the glove compartment.
c) Loaded and under the seat.
d) Unloaded and locked in a DOJ approved firearm container or in the trunk.
If you can't pass the test without studying you should take a think twice about purchasing a gun.
6. Fill out ardous paperwork and purchase your gun.
7. Read about gun safety on the Internet or take a firearm safety class. You can sign up for the class at Turners.
8. Take your gun to the gun range a shoot it quite a bit until you get the feel for it. At least 500 rounds in a handgun.
9. Buy a DOJ lockbox if you have kids.
Have fun.
Also try .40
I know people who didn't like other calibers and then tried .40 and got it. It balances capacity, stopping power, recoil, etc., pretty well for home defense, and many police departments are switching to it.