This sounds a lot like my daughter:
"Hyperlexia, type III
This is a less frequent form of hyperlexia and it is the one sometimes inappropriately diagnosed as “autism” because of the failure to distinguish ‘autistic-like’ symptoms from autistic spectrum disorder. These children also read early, often show striking memorization abilities, and sometimes have precocious abilities in other areas as well. They may have ‘autistic-like’ behaviors for a period of time. For example, they may show unusual sensory sensitivity (to sounds or touch or taste). They usually seek, and do not avoid affection, and in that sense are more social, outgoing, interactive and less withdrawn than children with autistic spectrum disorder. They do tend to make eye contact and can be very interactive with persons close to them. There may be fascination with, or intense insistence on, routine and resistance to change. These children seem quite bright, inquisitive and precocious in some areas overall. Interest in, and mastery of, reading coupled with memory powers memorization is conspicuous and often quite amazing. There may other ‘autistic-like’ symptoms or behaviors as well, such as ‘stimming’ for example But over time the autistic behaviors and symptoms fade and, as it turns out, these children then are quite normal (neurotypical) for their age."