Fetching details from the dictionary...
honor student; honours student; model student; prize pupil
彼女は昔、優等生だった。
She was an honor student in the past.
彼はまさに優等生タイプだ。
He's exactly the model student type.
うちの子はいつも優等生ぶってばかりいます。
My child is always acting like a model student.