When should i text her?

Thursday night my school had a movie night, and i suddenly found myself called over by a girl who i rarely talk to. She and her friend from another school started making small talk with me, and thats when i brought up the fact that i recognized her friend from a party i had gone to. They then invited me to sit with them, and when the movie starts i realize everyone in their group leaves except the girl, who is sitting next to me--a stranger--instead of going with her friends. We converse a bit, and her friends come back telling her that they are leaving for sushi, and that im invited too. So the girl hugs me goodbye, and i say that we exchange numbers. But she acts a little bland and says "oh...okay." And we do. I text her around four hours later, and she never replies. Many people noticed her coming on to me, texting me from across the room to make a move and stuff. so im a little confused. Was she weirded out? Or is it possible that shes just a bad texter? I want to text her again, but if i should, the real question is when? I got her number thursday night. Its now saturday night.