I only started to learn to read when I was eight but once I started I whizzed though all the standard school books (from "Janet & John" to the red, blue, yellow, green books) in a year and moved onto adult books (Azimov, Heinlein, Clarke). As far as I know, this wasn't a developmental issue, it's just that no one had bothered to teach me! Because of this, I made sure I taught my kids to read as soon as possible. My eldest (also AS) had already read the books he was supposed read at secondary school by the time he was eleven - that really pissed off his teachers 
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Diagnosed: Asperger's Syndrome (ICD-10)
Self-Diagnosed: Aphantasia
Your neurodiverse (Aspie) score: 152 of 200
Your neurotypical (non-autistic) score: 46 of 200
Listener of all things noisy, viewer of all things bloody, writer of all things sh*t.