She’s probably scared, or maybe her parents don’t want her dating anyone. See I’m trying to give you something to go on, because most girls don’t ignore feelings for no reason. If they have them, then they care for that person. Put yourself in her shoes, what if she’s been hurt by others or isn’t allowed to date. It’s hard to run away from feelings and if she’s been managing to do this for some time then you’ve got to acknowledge that it’s been hard for her. I don’t think it’s anything against you, I think it’s more of a personal thing between herself. Your best bet, is to be there for her, it’s doubtful that she wants you to leave. Im sure whoever she is, is happy to have you in her life. That’s regardless of how she feels because good people are hard to find.