If she turns out to be HG+ a sheltered church school with small classes and willing to skip her up when she needs it would be just what she needs.

Have you checked with the local schools that they are actually prepared to let her into first grade? If she is age appropriate for emotional development she probably won't be the least emotionally mature in first grade - there is a fairly wide range. And maybe she will be more emotional all her life anyway.

All the best.