My 12 year old has been a great reader since she was a baby. She didn’t read then, of course, but even as an infant she would sit happily on your lap for as long as you’d read to her. When she was four she could read those Dick and Jane books. We aren’t sure when she learned how to read, she just figured it out at some point. By kindergarten she was independently reading chapter books. Her reading ability has always been off the charts for her age, but I don’t know her scores. If the schools here use that system, they don’t share it with parents.
My 8 year old took his own sweet time learning to read. He would scream if you tried to sit and read with him as an infant or toddler. He thought books were only good for chewing on, and would even yell at me if I tried to sing the ABCs with him. He had zero interest in learning to read and only learned the ABCs right before kindergarten because I found an alphabet book about bugs. He is obsessed with bugs. In kindergarten and first grade, his reading level barely met the minimum grade standard. Sometimes he would act like he couldn’t read when the teacher tried to assess him so he could just go do other things. For half of first grade he worked with a reading specialist until suddenly, he started reading everything. It was like he just decided, “OK fine, I’ll do it already.” In second grade, his teacher told me he was one of the best readers in the class. She said she would never think he’d been referred to the reading specialist only the year before. He’s in third grade now and reads very well, but isn’t an avid reader like his sister. Unless you give him a bug book.
My six year old is in first grade and is having an easy time with reading. He is enthusiastic and motivated and easily learned the kindergarten sight words. His kindergarten teacher told me how he’d done on one particular reading assessment and said in all her years of teaching she’s had very few kids score that well at his age. He can read a lot of words and can sound out many others, but he’s not at that fluent reading stage yet. I don’t anticipate any problems since he is picking it all up so well and loves school to the point where he’d probably be happy to move out and just live in his classroom.