There is also a large genetic component and because it is part of a bigger constellation of neurodevelopmental disorders, you’ll often notice that it overlaps with many other diagnoses. So, it’s not uncommon, especially for me as an assessor, to see children a little bit later in life who have had multiple other diagnoses.
And even though a lot of times parents start noticing differences in the first two years of life, sometimes not everything is as well understood until later, especially for higher functioning individuals (or more appropriately, people who need less support). Or, for example, cis-gendered girls are often diagnosed significantly later than cis-gendered boys.
One of the important things in clinical psychology is to understand all the different components. To say, ‘What might be causing these difficulties?’ and ‘How do we address them in a way that is comprehensive?’ Not just targeting one area, but understanding the child or the individual as a whole.