Why is she acting this way? Read fully! What is going on? Why? Does she like me?

So there's this girl that i really have a bad crush on. We have known each other since 6th grade. We used to talk alot in 9th grade but not as much anymore. I feel like she like me at least a little but i don't know why i feel that way. I need to do something about her. We're not dating yet. There will be a dance in 2 weeks at school. She is shy. She is always with friends and she don't stay for lunch or come back after. I only have during class or passing but id rather it be in class. She sits next to 2 of her friends. Lately when I have tried to talk to her she usually give like one word answers and answers in a quieter voice than she does with anyone else she talks to. She doesn't talk unless I start to talk but even then she barely talks at all. I have caught her looking at me from behind a few times. Like during passing period. Her friends on Friday were looking up every time I came around them. I don't understand her at all. Today I told my friend to ask one of this girls friend if this girl really did like me? Her friend told my friend that she could not tell him. In class she always has her iphone next to her. Sometimes she texts when the teacher isn't looking. I have noticed that when she walks past my chair first thing in the morning(first period) she always taps it or knocks on it once and acts like nothing happened. She has also been talk about her ex-boyfriend a lot during that class where I sit at the same table. She says that he has been flirting wuith her and calling her babe. What's going on? She only does it once but still why has she been doing this? Does this mean anything? What does that mean? Should i ask her to a school dance?

She is either really shy or just messing with you. You need to find a way to text her and ask her to the dance without her friends around. If she says yes then she likes you. If she says no then she doesn't.Simple