, six or seven years of age), because until that time most of the behaviours exhibited by children with ADHD are typical of all children in
the preschool years. (They may be more severe in preschoolers
who have ADHD
, but since some kids who are highly active in their preschool years definitely don't have ADHD, it's better to wait.)
A lot of what you are describing is typical toddler behaviour - defiance, ignoring "no", climbing all over things, etc.