T.U.
I am a director of Creme de la Creme a Private Preschool here in Plano.
It is very a very normal reaction for a child especially if they have never been in care and have had family change. What I advise new families is to keep drop off time and pick up time consistent. I also give families a copy of the schedule we keep at school so that they may do the same at home on the weekends. It will usually take a child any were form 4 to 6 weeks to adjust fully to the schedule, the environment and the teachers. She needs to begin to build a relationship with the teachers in the room (They usually attach to one). This process will get better you just have to stick to the consistency of the schedule and not let her talk you out of taking her to school. Children tend to know when families are also apprehensive about situations so the more convincing you are to her that this experience is something good the better it will sit in her head throughout the day.
Hope this Helps! :)