Hi - Relatively new myself, but wanted to lend support, as we can relate to much of what you have shared. DD8 is bright, incredibly intense, exhausting at times , an independent thinker, and young for her grade. Despite being young for her grade, we also struggle to keep her challenged in school, and our school's gifted program doesn't start until this year (Gr. 3)...currently seems like the process is taking forever.
One of my DD's former teachers called her "immature" in some ways (while also admitting she was one of the brightest students in the grade), and although I understand what she was describing, the teacher seemed quite unfamiliar with asynchronous development. I have found quite a bit of literature on this, though, and I knew that this was at least part of what she was describing. Forums like this one and SENG are extremely helpful.
DD often comes off as "bossy" to other children, although she is starting to get better. Her incredible enthusiasm and big ideas draw kids to her, but then she wants to "manage" the play. Some of this seems to be improving with maturity and our constant coaching. There is hope. This year, DD came home and announced she was elected to Student Council!