Maybe the answer is, the earlier, the better.
Most children learn to read in the first grade, at age six.
If you add all the pieces up, babies learn language faster. Their brain is developing faster at this time. Titzer is a professor and researcher in the field of infant learning at Southeastern Louisiana University. He believes that the best time to start teaching children to read is when they are three months old. Titzer believes that explains why there's such a reading problem in the United States.