It depends. Is she shy or outgoing? If she is shy, then she probably won't tell you. But you'll catch her staring at you, and her face will probably go red when you talk to her. (I personally stumble on my words when I'm around my crush) If she is outgoing, then she might ask you for your number/ tell you that she likes you. If her friends ask you bout her, that is a good sign. Regardless of her personality, if she texts/talks to you a lot she probably likes you. Give me more details on her personality, and how close you are to her.