Age
Based on the fact that he was 4 years old when his great uncle died, entailing the estate away from the Dashwood girls, we can conclude that he is 5 when the novel opens.
Family and Situation
Harry is the son of John and Fanny Dashwood and the heir to Norland Park in Sussex. This makes him the nephew of Elinor, Marianne and Margaret Dashwood as well as Edward and Robert Ferrars. Mrs. Ferrars would be his grandmother, as would Mrs. Dashwood, though the latter is not a blood relation.
As a very young child, we know that Harry inadvertently convinced his great uncle to carefully entail the estate so that it would come entirely to him and pay out no funds to his aunts by deploying “such attractions as are by no means unusual in children of two or three years old; an imperfect articulation, an earnest desire of having his own way, many cunning tricks, and a great deal of noise.”
