Does anyone know - if it is developmental, at what age they would typically grow out of it?
I am not a professional, so take what I have to say with a really large grain of salt
Both of my older daughters lagged with reading with some of the same symptoms you've mentioned above - one was due to vision, one is an LD. The age that I have seen teachers across the board (both in their classes and in my ds' classes) was as easy as K and for sure by the end of grade 1. Children in our school district who are not on grade level at the end of first are recommended (strongly) to go to summer school to catch up, and if that doesn't work 2nd grade is where the schools start targeted reading interventions. Note - this is the age that the teachers were pointing out issues with typically developing kids, not HG/+ kids - my dd who has the LD slipped under the radar until late 2nd grade and even then wasn't thought to have an issue because she was reading at grade level.
If you're worried about anything related to reading, I wouldn't take a sit-back-and-wait-and-see approach - reading is such an integral part of academics and overall intellectual growth. My dd's vision issues weren't caught by her regular eye dr, but were obvious on a developmental optometrist assessment. Within just a few months of starting vision therapy she just skyrocketed in reading ability, and perhaps the most important gain of all, for her, was she turned into a kid who loves loves loves to read. I don't suspect an LD from anything you've written here, but fwiw, early understanding and remediation was really important for my dd with the LD. It would have been *so* helpful if we'd been able to pinpoint her challenges and start remediation as early as first grade.
Best wishes,
polarbear
