It is common advice to "write what you are passionate about." Think for a moment; does it matter what you write if no one will listen? There are multiple reasons to doubt the importance of a person's opinion, but one of the ones that many students will have to address is age. You haven't lived as long as others, so your opinion doesn't matter, right?
The SAT essay prompts of the past have often concerned questions about where information should come from. Should you trust yourself or an authority? The experienced and elderly or newer and more creative ideas? You may respect tradition a lot (or not at all), but it seems a little odd to argue against listening to young people when you are a young person writing an essay and asking people to read it. At the same time, no one cares if you think that you are smart! No one cares if you think that you are smarter than some older people. Instead of talking about yourself, show your ability to reason by giving a concrete example from current events.
Check out this current event about a student who found something that professionals missed. This baby dinosaur wasn't necessarily found through skill, but it took knowledge and intelligence to recognize the fossil for what it was. You can find more details about the story here.
This would make an excellent current event to use as one of your five prepared examples. This story has many other themes besides age. What does it have to say about luck, motivation, success, ease, or discovery? All of these topics have formed previous SAT essay topics. If you plan to use this story as one of your example choices for the SAT essay, be sure to make a note card and memorize the important facts about the story. Using proper names will make you sound informed!