Children who have ADHD often show symptoms while they are very young. Parents may notice their child is more active, talkative, impulsive, or has more trouble listening or following directions than siblings or playmates. When should I seek help, and where do I start? A child can be evaluated for ADHD beginning at age four. Some children will have an evaluation in kindergarten or first grade. Many parents wait until symptoms are causing difficulties at home and in school before seeking an evaluation.