I think that feeling is why we are so drawn to stories that have a young protagonist. Look at Harry, he saved the wizarding world when he was still in his teens. Katniss won the hunger games (more than once) and spearheaded a revolution. The Pevensie siblings became kings and queens of Narnia before they even finished school. So it's no wonder that the Alex Rider series is so popular.
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In Point Blank Alex is sent to infiltrate a very prestigious private school. So prestigious they only have a handful (aka less than 10) of students at a time and the fees are over $15,000 a term. Right away Alex realizes that there is something suspicious about the other students. They're all exactly 14 years old, they all have wealthy powerful parents, and somehow they all seem to have the same mannerisms. Could they be brainwashed? Or is there something more?
Point Blank is filled with everything a good spy novel needs. An effortlessly cool yet supremely talented spy (that's Alex), creepy locations (that's the school), a villain who is simultaneously terrifying and intriguing (not gonna tell you, you'll have to read the book yourself), and plenty of ingenious gadgets.
Going undercover...that's kids stuff.