Hardly any ever get moved up one HS starts. In the younger years they will always move at least one B team kid up to keep the illusion that you have a chance .
There have been many girls moved up in HS depending on the HS they attend. If you don't attend Northport, Mt. Sinai, ESM or Smithtown you don't have a chance of moving in the HS ages.
As far as the younger ages go, movement depends on where you live as well, and who you take lessons with (at $75 an hour….LOL).