Can you have ADHD and also be a quiet kid?

Yes, you can have ADHD and be a quiet kid.  I was quiet and thought you had to be hyper to be ADHD.  This delayed me getting diagnosed until I was an adult.

Sometimes people call non-hyperactive ADHDers ADD not ADHD but officially it’s ADHD-PI which is the primarily inattentive type.

There is still hyperactivity of the brain with thoughts and emotions.

Seek a professional opinion from an ADHD specialist.