I think it's terrible that kids hard work and potential together do not speak louder than their age.
My DDs old coach said to me this past weekend he absolutely could see DD compete in college. I laughed and said she is too old, having just started at 12. He said, "no, SHE can do it. Can everyone, no? But she can." Unfortunately, she will never get the chance, because being 13 (and tall) no one will give her a sideways glance for JO, and where we live and that we moved is out of our control. She will compete xcel till we move again, and then she can either switch to USAIGC or maybe petition into optionals, although her current gym said that is no longer allowed.. She would do ANYTHING to train JO hours and intensity, but we bought into her dancer body type and had her in ballet for the important gym years. Sigh. The system of it all is depressing.
Btw, in your case, your DD is definitely not too old, and I would be seeking a new gym; one that is at least open and transparent about possibilites.