What does she mean by saying I am "hard to read"?

When I have said that in the past its because I was feeling a lot more than what the guy said he was and for me it was hard to determine whether or not he was feeling the same way such as love before I blurted it out. Emotions are a huge thing for women. Sometimes we feel too much, too often and too hard. Taking the chance of saying I love you or I only want you or anything that leads to exclusivity is hard for some. I say the next time you two get a chance do something really sweet and romantic together. That will either break the walls down and allow her to open up and tell you how she is feeling or it will bring out deeper feelings that you hadn't recognized and you will open up to her and she'll reciprocate.

Well confront her about it, I say that about practically every guy because one minute their interested and then they act as if I'm dead! Or they tell me they like me but don't ask me out on a date or anything. I can only think of the reason that your affectionate with her and everything but maybe you haven't asked her to be your girlfriend and she wants you too but doesn't understand why? That's all I can think of

at her age, it probably means that she hasn't yet determined how to manipulate you.