"A child who is aggressive, noisy, exhibiting lack of motor inhibition (wild, acting out) is attended to, and this behavior is characteristic of boys. A child who is well behaved, quiet, and apparently compliant will often be overlooked, sometimes despite underachievement. Such a child is quite likely to be a girl. Consider the following scenario:
A schoolteacher tells students at the beginning of a lesson that they should be sure to ask for help whenever they need it to understand the lesson. A boy with AS has his hand raised from the outset and won't put it down. The subject matter is after all, new and he has taken the teacher's words literally. A girl may have taken the teacher literally as well, but she resolutely keeps her hand down. She has known too many occasions when people's words did not represent their intention. She has been ridiculed or criticized for missing point. So she keeps her questions to herself and, in this isloation, misunderstands a good many things, therefore failing the lesson. In this hypothetical example, observers would easily detect the literal-mindedness, with a touch of perseveration, in the boy's response, which so clearly manifests AS cognitive traits. The girl, though she has the same traits, handles them differently in her efforts to navigate through a confusing world. But she is AS -- and her life challenges are rooted in AS -- just the same."
-- Jean Kearns Miller, "Under-diagnosis in Women", Women From Another Planet?
This definitely explains why I wasn't diagnosed until my forties.