I am going to be as honest and frank as I con possibly be. You might not like the answer i give but I am pretty sure it is true.

The truth is almost NOTHING can prepare you for becoming an agent, at least not for the agents that are actively collecting intelligence in foreign and possibly hostile territories.

You can try to apply at the CIA (That is the main intelligence office anyways) as a regular intelligence 'sorter' for the lack of a better term. That would be basically your everyday desk job with regular colleagues and bosses, with the exception of the fact that you might not be allowed to diverge classified material.

But if you want to become a Field Operations Officer (or in urban terms, a spy) you have to pass psychological and physical evaluations before they even allow you to enroll in training.

Both types of jobs offer adequate training and would most certainly prepare you as well as possible for whatever you might have to face. But in the end it all comes down to your own experience and judgement.

But when you think about it, there's hardly any way for you to prepare yourself well for the job before you apply. If we could do that, then there's hardly any need for training. And then we could all become super spies without much work.

If there's anything you COULD do, it's to stay in school get good grades, and get a (few)good college degree as that would certainly propel you to a more valuable with better pay too.

In ShORT STAY IN SCHOOL to get in CIA (I know it's hard, heck I'm 16 too XD)

See my sources for more information.

1. Get your degree.

2. Live extensively in a foreign country, particularly one in which the U.S. has a strategic interest.

3. Become highly fluent in the language of that country.