alot rides on which class of cdl you're shooting for. i have an arizona-issued class B cdl, which allows me to drive any single vehicle with a gross vehicle weight of more than 26,000 lbs, but you need a class A cdl to drive any combination vehicle where the trailer grosses over 26,000. if you just wanna drive straight trucks, i say it's an easy thing. you should be able to study up for the written test, when you pass that you get your learner's permit. the next thing you need to do is get a medical examination, the D.O.T. physical. this basically says that you're fit to drive. it's not anything challenging, as long as you aren't missing any limbs or have diabetes or something like that, you'll be fine.
i would reccomend finding a job that will train you into the cdl you're looking for, especially if you're shooting for the class A licsense. tractor-trailers are a tricky animal, one which i'm not willing to play with, hence my class-b. but i do all right, there's plenty of work in straight vehicles if you know where to look.
have a look here, this is california's official information on obtaining a cdl
good luck.