Something is happening with her that you are just going to have to wait and see. Perhaps her friends have said something about you that has embarassed or frightened her. Or something you have said to others has been reported to her (but not as you said it or meant it).
Or it could be just as PDM has said - an attack of shyness.
In any event, to push will be to further drive her away. Be friendly, but basically wait and see.
