She knows there is Kindergarten coming up.
Her reactions is normal.
Get the book "The Kissing Hand." It is good. I read that to both my kids before they entered school.
My son, was a homebody. And was SO attached to me. At 4 years old, he went to preschool. He was more conducive to it at that time. Versus, his sister went to preschool from 3 years old.
In any event, a child will be fine.
LOTS AND LOTS of kids, when entering Kindergarten, may cry or feel lonely for their Mommy. The Teacher knows that. It is normal.
They will get over it.
You will NOT damage her sensitive self-esteem. Self-esteem has NOTHING to do with, being separated from Mommy or not. It is something that is, about Self-Assurance. Teach her that she is herself, and knows herself and she is her own, person. And that, it is normal to get nervous. Even adults get nervous. But it is fun... to learn new things and see other kids. And she can tell you things/how she feels anytime... and its okay. But that you will help her talk about it.
You will NOT damage her. ALL kids get nervous about going to school. And the parent.
In most States, Kindergarten is for 5-6 year olds. BUT, if a child is already 6 or turning 7, a school may put the child into 1st grade. That is how it is at my kids' school. Public school. So... make sure... that if you hold back your daughter and enroll her in Kindergarten later, that you can enter her into Kindergarten. See what the age/year cut-offs is, in the school your daughter will attend.
ALL kids, are nervous when going to school. And there is a separation-anxiety... for the child or the parent.
This is normal.
It is a Rite Of Passage... for the child AND the adult. It is a normal transition, to life's phases.
And YES... many kids do cry, when going to Kindergarten for the 1st time. Your child will not the the only one.
At my kids' school... the Teacher is prepared for it, AND the school Counselors... are at the ready for it too... they do observations of the kids during the first few weeks of Kindergarten, and will help guide the little ones to adapt to school.
Don't worry.
A child, at this age, needs to learn to fly.
And they will.
My son, who is a homebody and is still VERY attached to me... adapted to school FINE. Like a champ. He loves school. And he has a very good sense of self, and is very self-assured. You teach a child to know themselves.... and to believe in themselves. That makes a difference.
I taught that to my kids since they were 2 years old.
All kids... are "sensitive." But they will be fine. It does not damage, their self-esteem.
For you: YOU have to realize, that a kid will or may cry when attending school at first. But don't transfer your fears/apprehension onto your child. It will make things worse. But let your daughter express herself. Sometimes, kids will surely say they are nervous etc., BUT that is your "cue" to be positive about it for your child, and to take the lead in it... in guiding her. That is how kids, reach out... by saying their nervousness about something. So instead of avoiding talking about it with her.... Compliment her.... ie: tell her "Wow, I appreciate you telling me how you feel. How grown up! Now, how can we make nervous feelings feel better?" ie: you can "practice" the morning routine about getting ready for school, putting her school supplies in a box and labeling it with her name, getting her school clothes ready etc. And so that she knows, the "routine" of things, before school.
Thus she may feel more "ready" for it.