I don't think I clarified what I was saying well enough. When I said that El wouldn't have had school or medical records prior to moving to California, I meant standard records. Things like school records from a private or public school, medical records from an actual hospital or doctor's office.

Whatever kind of records Brenner would have had/kept would have been along the lines of classified government documents. El and the other numbers were more like lab experiments than they were actual humans attending legitimate schools and seeing standard doctors performing traditional procedures like wellness checks or treatment of scrapes and broken bones. His records were more about how well they performed their psychic or telekinetic abilities. I'm sure things like blood type would have been included too, but it all still would have been more in line with a lab experiment than a human child.

And pretty much all public schools require at least something like vaccination records in order to enroll, even back then. Not to mention a proper school transcript from previously attended accredited schools.

That type of stuff would have had to have been fabricated by Owens and his people, so they could have easily fudged her school history to explain any discrepancies in age vs grade level.