Why won't he talk to me?

There is this guy in my school that i really like who is emo, and his name is Luis. Although i am emo, i usually like don't like emo guys, but this guy i just can't get out of my head. The other day i saw him at lunch sitting alone @ a table not eating anything like he usually does, and i went to sit with him cause i do the same thing every lunch and it is really fustrating. So i sat across from him, and said "Hi i'm Cristie." And he said "Hello." And since i sat there he kept like half smiling like he was trying to hide his smile, and he would stare at me and when i saw him stare at me he would look away. It was very akward, but i really want him to talk to me, and he is so quiet. Do you even think he will talk to me, if u do, how will he.