DC18 (PG, E2) loved documentaries on television and started reading and spelling more complicated material (many learning disabilities), although he verbally expressed a lot more complicated stories. Counting, days of the week, time, and money were concepts he already knew. He loved learning computer games and board games as well. He asked a lot of questions when he was interested in learning material that was above his reading level, too, and he amassed a lot of knowledge of history and sports. Problems started almost immediately with acceleration needs but age-level writing and slightly above reading levels but a much higher understanding of material presented.
Around the start of kindergarten, I started as my aunt's nanny and began to teach him at his own level when we were at home, as it took several years to fully understand his learning needs. He was very interested in social philosophy/human rights/meaning of life at around 7 years old and enjoyed discussing this with adults and having me explain some of my college coursework in it.
DC16 (MG) was reading and spelling ahead of the curriculum (easy readers/children's books before starting kindergarten) and loved doing some math problems. She was generally happy with school, albeit bored sometimes, as she was ahead of many of the other children (and young for her class). Most of my siblings had experiences like this, too (kindergarten skills around 3.5-4 years old).
DC13 (HG) was quite a bit ahead in math (adding/subtracting/grouping numbers for multiplication) but not in reading or writing (easy readers around the start of kindergarten), and he has needed some harder math opportunities. Reading and writing have been in the upper part of the class but not significantly ahead.
I (PG) was near the end of the kindergarten curriculum around 2 years old (as it seems your DD3 is) and was quite far ahead by the time I entered kindergarten (at 4.5, when my sister was starting, out of convenience). At the end of that year (5.5), I was doing the following:
Reading: Mostly nonfiction science, history, and philosophy/religion at junior high/high school+ level when I read at home. I had some problems with reading older material and becoming scared of what I read sometimes (natural disasters, war...)
Math: Adding, subtracting, multiplying, dividing, learning about how to graph equations from older siblings, and playing with a graphing calculator when I was at home
Writing: Early/mid grade school level, easier with a computer than by hand
I hope that this helps
