Harry doesn't think much of himself early on. He's spent his whole life being told he was garbage and he's nearly come round to believing it. But suddenly he's whisked away to a magical school and told he can practice magic and that he once destroyed the most evil wizard anyone's ever seen just by being himself.
That's a lot to take in when you're eleven years old. A lot of Harry Potter and the Sorcerer's Stone involves Harry trying to figure out who he is: not just where he comes from and why he fits into this world, but also who he is as a person.
Questions About Identity
At what points does Harry's identity start to come into focus for him? Why are those moments important?
In what ways do the Houses determine your identity?
How does Harry's identity affect the way people react to him?
How do Ron and Hermione's identities develop alongside Harry's?
Chew on This
Identity is determined by birth and destiny, and Harry's was cemented the day his parents died.
Identity is a question of personal choice, not fate.