My friend can't keep her mouth shut?

I have a friend she is such a sweet person. The only thing is even though she sees me as a confidant, I cannot confide in her at all. I just got a job a month ago and I am in the process of orientation right now. I did not tell her because I am not ready for "the world to know where I am working" yet. In the past, she told everyone at church where I worked. I feel so bad because we talk on the phone sometimes twice per week. How do I handle this because I know she'll feel hurt when she finds out I have been keeping this from her.