Jag tror att det är Chance Fortune and the Outlaws av Shane Berryhill. Plottet från Goodreads verkar matcha riktigt bra:
For as long as he can remember, fourteen-year-old Joshua Blevins has wanted to be a superhero. He has the brains, the passion, and the heart. There's only one problem: he doesn't have any superpowers. But Josh isn't about to let that stop him. Determined not to give up on his dream, Josh enlists the aid of his mentor, Captain Fearless, a retired costumed adventurer, to gain entrance to the Burlington Academy for the Superhuman under the false identity of Chance Fortune--a superhuman with the power of having unnaturally good luck. [...]
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