Y would she ignore me?

Ok theres a girl i really liked we used to hangout all the time cuz she was a homies sister. She used to flirt with me alot shed send me messages like hey hoe whats up n stuff like that shed always laugh at my jokes, call me ugly but playfully, go wherever we went, id catch her staring at me sometimes, one day at school we saw eachother in th hallway and she smiled and stuck her tounge out at me. These little signs that she liked me but she never actually said it. Anyway her being my boys sister kept me from the courage to tell her how i felt and ask her out until 2 years after we havent seen eachother or spoken just because if she didnt it would b super akward spending all that time together. But the 2 years past and i finally tried to start the conversation where i told her my feelings n ask her out so i sent her a facebook message(only bc i had no other way to get ahold of her) just a friendly "hey whats up i havent talked to u in a while" and she straight up ignored me. She accepted my friend request but ignored my message? So i thought uk maybe she didnt kno who i was so i asked my boy for her # and got the same thing ignored. I was never mean to her or had a fallout so why would she just ignore me like that? Do u guys think she liked me? And either way y not just say no y ignore me?