is your friend.
Seriously, you can find answers to all your questions that way. It will take a lot of time and effort, but you will be rewarded.
Since you're in California, start here:
California Gun Laws
Another suggestion: Read! Buy and read all the gun magazines & periodicals you can find. Check the big book stores, like Barnes & Noble and Borders. You would do well to read anything by Massad Ayoob.
You can't legally purchase a handgun until you are 21.
We'll try to answer your questions here, but please try to be specific.
And join the National Rifle Association.