What does "before kindergarten" mean? In the mornings? Or before she was old enough to go there? I started kindergarten at age 2 (like described in Wikipedia) and I suspect that is not what you mean.
Kid #1 was and still is an oddball in a number of ways. Learning to read so early seems to have given her some advantages, like being able to consume volumes of information at a young age, but she'll have a harder time in other ways.
Where do you live?
My son started preschool at 2.5. I guess anywhere between 2.5 and 3 is typical here. Then pre-k at 4.
Where I live it’s private. So parents send their kids to pre-school at 2.5-3. But by 4 the public schools will take them in.