Nico is incredibly smart, coming from a rich family, he of course was given the best education. Not only that, he was just naturally a smart kid.
He excels in school, which is why many teachers found it weird that he asking Mika to tutor him. A lot of people would hear him claim he fail a test or didn't understand a certain topic.
The truth of it is, he just wanted an excuse to spend time with Mika. Every time he goes to her house to study, he claims he already did his work and just wants to hang out. Which she did catch on, but didn't say anything about it.
