[ Singles & Dating ] Open Question : When and How should I tell my love to her directly?

I love a girl named Monisha. I love her so much. She is just a single year younger than me. We are studying in the same class. I am 16 and studying XI. I am loving her for six months. I already expressed my love to her via a third person; but she rejected me. But now, I find some signs of love at her on me. But it's not sure. I am so confused on what I have to do. When and How should I tell my love to her directly? Please guys, help me.