The age at which children start to learn to read seems to be relatively unimportant; indeed, there are no serious or permanent side-effects even when it is delayed until age:

Question

Quizplus · Accepted Answer

Research suggests that children can start to learn to read between the ages of 4 and 9. However, there is no evidence that starting at any particular age leads to permanent side-effects. Children who start later may even catch up quickly and show similar reading abilities as those who started earlier. Therefore, it is reasonable to say that starting at age 7 would not result in serious or permanent side-effects.

The Age at Which Children Start to Learn to Read