In my freshman year, I took a world history class and since then, my love for history grew .

exponentially 意為「呈指數性地、爆炸性地」，常與 grow/increase/rise 搭配，表示「快速且大幅地增長」，完美呼應「自從修了世界史後，對歷史的熱愛大幅增長」的語境。