Hello! I’m an introvert with inattentive ADHD! It took me a very long time to come to terms with it and also get a diagnosis because I never had many of the “stereotypical” aspects people usually associate with ADHD.
The important thing to remember is that what people assume to be symptoms are often set by neurotypical people, and also, similarly to autism, the traits are often heavily influenced by male stereotypes.
Neurodivergence affects men and women differently, because of the way girls and boys are socialised differently. ADHD women are more likely to be inattentive types than men, and vice versa, although not always the case of course.
So yes, it is very possible to have ADHD and also be quiet. You’re not alone :)