Welcome Amber! This all sounds familiar to me. Before my DS started kindy, the school tested him on WJ-III. Since we had DYS in mind, already having IQ scores, we asked if they could get broad math and broad reading scores. The school tester told us she was only able to norm for 6 year olds (and DS had just turned 5), but she figured it anyway, telling us that the actually scores would be higher, but she couldn't say what they would be.
On a personal note as to public school, our DS did fine in regular, age-based kindergarten, but we did do a lot of advocating to get him appropriate work. He ended up skipping 1st in the same local school district, and doing fine in 2nd grade, with lots of advocating on our part. We do live "near" a large metro area, and an opportunity came up to transfer to a public HG school, so we did that mid-year, which is working fine, with no advocacy necessary as of yet. So, as others have said, I think there are ways to make things work wherever you happen to be, whether it be lots of advocacy at the school, afterschooling, homeschooling, etc., but the important thing is that you are aware at a very early stage of potential issues that your child will face in school, and so you will be able to make it work.
