Generalized anxiety disorder is the diagnostic name for kids, teens, and adults who meet the criteria. Oftentimes people will say they have anxiety, or general anxiety, without quite meaning that they meet all of the criteria. You can find a screening tool* for kids and for adults put together by the Anxiety and Depression Association of America (*which gives you information, but you will want to meet with a counselor, social worker, psychologist, or psychiatrist for a true screening).
What makes anxiety a disorder?
Generally speaking, an anxiety disorder gets in the way of your everyday life, and is harder to manage. It comes up in multiple environments, so home and school, or work and home.