I think this is comical. Sorry, but there is no way a three-month-old is going to exhibit any kind of meaningful intelligence level at that age, or any other age below school age.
They measure based on typical stages of cognitive development, not their ability to perform calculus computations.
This is how they know if children have developmental problems or not.
I.e, you don’t have to wait till age 18 to realize your kid has a developmental problem.