You could just have a gifted child on your hands. Aldo keep the word hyperlexia in mind if she starts reading with no input from anyone. I mean reading.....not just memorizing words from sesame Street or by using context to figure out a word, like on a tape box, but everything. semantic-pragmatic disordered kids also read and early, but they do the memorizing. I remember that my son had a few strange little things at that age, but he wasn't talking that early.
My 6 yr old ADHD son lines up his toys clear across the living room. He sorts them by size. He puts his dinosaurs into circles, littlest on the inside, largest on the outside. If he makes a mistake he has to start over. My sister in law said her oldest son did the same things when he was little; he is now going to VA Tech majoring in astrophysics. So a little Obsessive Compulsive is not necessarily a bad thing. My son also reacts to loud noises, has problems with tags in his shirts, and textures with food. A lot of repetitive behavior can mean a mild form of autism or a related disorder. If she is not too responsive she could be mildly depressed. It could be a number of things and you could have her assessed by a psychologist or psychiatrist.
If you have read any of my other replies, you know I am big on diet changes to see if there is an improvement in behavior. Eliminate artificial dyes, flavors and preservatives from her diet. Limit sodas, juices, sugar, and dairy products. Cook from scratch and give fresh fruits and vegetables as snacks and limit the junk food. Try this and see if it helps her behavior and she becomes more responsive.
Try reading "Special Diets for Special Kids" by Lisa Lewis. Some good sites are drrapp.com, foodallergy.org, greatplainslaboratory.com. You can type in autism and Asperger's syndrome with your search engine and get more sites than you probabaly want.
Dear Ms. Maroney,
You may be witnessing the onset of some obsessive compulsive traits or an organized obsessive compulsive disorder. It's really not possible to know at this point.
There's nothing you need to do about this at this stage, in any case. In most ways, it sounds like your daughter is developing fine. Focus on her many assets and positive developments, and continue to support these. You needn't intervene in relation to her idiosyncracies.