The smartest students we meet never talk about how smart they are. In fact, they spend a lot more time talking about what they wish they knew more about.
Colleges look for students who are intellectually curious, students who are academically confident, but keenly aware of just how much more there is for them to know.
If you've taken hard classes in high school and done well in them, you should absolutely be proud of that. It means that you've taken your genetic hand of intellectual cards and combined it with a good work ethic. Those qualities will take you a long way in life.
But it's important to remember that success in high school doesn't make you a know-it-all. In fact, no amount of schooling makes you a know-it-all. There will always be subjects you haven't yet been exposed to, theories you could better understand, or new perspectives you haven't yet considered.
The smartest students understand this. They don't feel compelled to talk about their GPAs, SAT scores, or number of AP tests they've passed. They're not resting on those accomplishments. They'll talk instead about their favorite classes, what excites them about college, and most importantly, how much more there is to learn.
Colleges like academic confidence. But curiosity is a much more appealing trait than arrogance is.