I have twins who are 5.5. DS repeated many stories from memory well before age 2, and figured out how to decode words around 3-3.5 years. By 4 he was reading easy readers independently, and between 4-4.5 he underwent a rather startling explosion of reading with very little instruction. At first he was just decoding, but now I would guess he is reading and comprehending at at least a 4th-5th grade level. He doesn't have as much interest in fiction unless the stories are short or humorous but will read transportation/ocean/space books for hours. He is not quite as mathy.

It has been fascinating, because DD (his twin), seem to enjoy math a lot more and adds/subtracts easily in her head, although she is just now starting to catch on to reading (easy readers) and really didn't have any sight words until around 4-4.5 so she was > 1.5 years behind her twin. DS seems HG+ to me and DD MG but but we are waiting for the WISC in December when they turn 6 and I think (and hope) DD will surprise us.

Because of the reading disparity, we requested they be in separate rooms for K in the fall although maybe it would have been better for them to have each other as peers. I am a little concerned about how it will go, and can forsee a grade skip but can't fathom skipping only one twin. Til then, I look forward to learning about the experience from moms of twins in this forum.