A: You have a soft heart and you are sensitive to your daughter's feelings--this is the most wonderful thing on earth and it will be a lifelong source of strength for your daughter. I encourage you to help her feel more comfortable by staying with her for short periods of time until she feels ready to say goodbye. Of course, this may be impossible if you have to be at work on time or if you have some other commitment that you can't change. But if you have the flexibility to help her settle in gradually and become more comfortable, it is better than leaving her crying (even though she may dry her tears and join the other children after a few minutes).
Do things slowly so that she feels in control of the situation and proud of herself; this will help her become a more confident and independent person over the long run. The important thing is that you have confidence that she will be ready soon, and that you let her decide when she is ready.