Young man, you disclosed certain information that makes me wonder about what is really going on. You stated that you met this young lady when she was still in high school and that she lied about her age. Now, it is hard for me to believe that you couldn't tell that most people in high school are still under-age! You are in college, and so I am sure you know what I mean as you were once in high school and under-age at that at some point prior to your graduation! It seems that this relationship should not have not happened in the first place. It also appears that even after you found out about her age, and your friends warned you against the relationship, you insisted on maintaining it (in some States this is considered as Statutory rape - if the girl was under age). The thrill for a young person in high school dating a college student is great. It seems that the thrill for the young lady is now over since she is also in college and can exercise her options!. You are not allowing her to do this, and this may be a selfish thing for you to do if you keep on hoping that this girl is even for you. 

Let it go young man!. My take on this is that your continued responses to her contacts in any form is unhealthy for both of you. Since you are the one asking the question, you need to take control of the situation and put it in its proper prospective.