State law does not give an age. But under that section it states if you are "prohibited by law from possessing a firearm" you can not carry a handgun in your vehicle (among others).
Under Federal law it states someone under 18 can not possess a handgun without parental consent. So it is a safe bet that you can not carry a handgun in your vehicle if under 18.
You will need to contact your local law enforcemnt for the answer since you don't mention what state, your age, etc..
Yes
Yes
yes your car is an extension of your home
If you can legally own a gun, you can carry in Alaska. See related link for more information.
Yes, you can carry a gun in your car in Oklahoma. However, it can not be loaded, and it must be kept in a case with all or at least part of the case visible.
In PA you have to be 21 to conceal carry (or carry loaded in your car) a handgun.
The state of Illinois does not issue carry permits, so it's illegal at any age to carry a gun in Illinois, assuming you mean out in public with a gun permit.
Within the constriants of Texas law, yes. Contact your local police for specifics.
If you carry a gun you can stop car jacking.
If you are not a felon, then the legal age is 21.
Penal Code 25850 PC makes it a crime in California to carry a loaded firearm in a public place, on a public street, or in a motor vehicle. This offense is generally prosecuted as a misdemeanor and carries a penalty of up to one year in county jail.