As long as you are 21 years of age or older you can legally carry a loaded gun inside your car in the passenger compartment of your car or in the trunk of your car without any problem.
That is unless you're a felon and in that case you are likely not allowed to carry a gun at all.
But as long as you're not a felon and are at least 21 years of age or older you can legally carry the loaded gun in your car.
As long as the loaded gun is legally yours and you are legal to have it then there's no problem with carrying a gun loaded or not in your car.