Harry Potter, the only son of James and Lily Potter, The Boy Who Lived, and savior of the Wizarding World was a hero since he was less than a year old. Despite the unfortunate circumstances under which he was raised until he turned eleven and was whisked off to wizarding school, he never lost his goodness, his sense of wonder, of his heroics.
But that doesn't mean that The Boy Who Lived was fully formed as soon as he was born. Everyone changes as they grow up and Harry Potter was no exception. He may have always been a hero, but he certainly learned to accept himself along the way.
He Went From A Cupboard to a Homeowner
The boy who lived in the cupboard under the stairs may have eventually earned himself a small bedroom at Privet Drive, but the major change in his circumstances came with the loss of his godfather, Sirius Black, in Harry Potter and The Order of the Phoenix.
With the death of Sirius, the last remaining member of the Black family, all of Padfoot's possessions were left to his godson Harry. This meant that Harry was then, and still remains, the owner of 12 Grimmauld Place.
Gained a Fortune
Even before inheriting 12 Grimmauld Place and the remainder of the Black Family fortune, Harry finally received the galleons, sickles, and knuts his parents left him at Gringotts. Harry may have entered Diagon Alley for the first time with no idea how he was ever going to pay for all his school supplies, but he left that shopping trip understanding that odds were, he would never have to worry about money again.
It's amazing to watch Harry's incredible appreciation for a cheap lemon ice pop on his trip to the zoo with the Dursleys only to see him buy some of everything off the trolley on the Hogwarts Express to share with his new friend, Ron.
Grow Into An Animal Lover
In Harry Potter and the Prisoner of Azkaban we hear that a very young Harry was once chased into a tree by one of Aunt Marge's bulldogs. He's no fan when she comes to visit with any of her pets in tow. This certainly changes when Harry receives a pet of his own, Hedwig, a birthday gift from Hagrid.
Beyond pets Harry also seems to have a certain affinity with magical animals in general, gaining the trust of Buckbeak the Hippogriff, connecting with Fawkes the Phoenix, and of course being able to talk to snakes.
He Learns How to Manage Romantic Relationships
Harry doesn't quite know what to do when a besotted eleven-year-old Ginny Weasley sends him a singing valentine in Harry Potter and the Chamber of Secrets. Two years later Harry is still struggling to even speak with girls (except for Hermione) and can't quite manage to get his first choice of partners to the Yule Ball.
Even when he does get together with Cho Chang in The Order of the Phoenix Harry is unable to understand her emotions or needs, despite genuinely caring about her. By the time Harry and Ginny can both it their feelings for one another at the same time it's clear that Harry, while still slightly confused, has matured and begun to pay more attention to the people around him.
Gains Meaningful Friendships
For the first eleven years of his life Harry's relationship with his cousin Dudley, the schoolyard bully, largely defined his relationships with his peers. Everyone was afraid to try and make friends with Harry for fear of retaliation from Dudley. This finally changes when Harry is able to attend Hogwarts. Hogwarts is not only a better school, but the first school in which Harry can exist without the specter of Dudley hanging over him. Harry's friendships, with Ron and Hermione in particular, are the envy of everyone who ever dreamed of the absolute best of best friends.
Goes From Being Ignored to Being Worshipped
It was not just friendships Harry lacked in his early life, it was meaningful relationships or interactions of any kind. As Harry says in The Chamber of Secrets, "I'll be in my bedroom making no noise and pretending that I don't exist." That may have been his fate on Privet Drive, but it's certainly not the same in the Wizarding World.
From his greetings at the Leaky Cauldron on his trip to Diagon Alley to his female irers in The Half Blood Prince, Harry learns and grows very quickly in having to pay attention to the people around him.
Gains All The Confidence
Harry isn't even sure he's magical enough to be at Hogwarts. Waiting to sit beneath the Sorting Hat he's afraid the hat may not declare a house for him at all because, really, he doesn't deserve to be there.
Compare that to the Order of the Phoenix Harry who guides other students in Defense Against the Dark Arts Training, declares his love for Ginny Weasley, and enters the Forbidden Forest alone to fact down Lord Voldemort. The Boy Who Lived has come a long way from avoiding his relatives just to sneak a snack from the refrigerator.
He Goes From Lucky to Talented
Harry, as a baby, defeated Lord Voldemort due to his mother's love and a large helping of luck. By the time Harry is hunting Horcruxes he has a plan and knows exactly what he plans to do to vanquish the Dark Lord one last time.
While Hermione may be the brightest witch of her age, Harry too has learned a lot along with way. From alohamora to a Patronus, he is very capable of fighting for himself. There is perhaps no wizards in Hogwarts history that was tested in his/her understanding of the defense against the dark arts than Harry.
He Learns What Family Means
From being an abused orphan to creating his own family out of his friends to finally marrying Ginny and fathering three children, Harry truly learns that he is not alone in the world.
From literally having no one except an abusive aunt to uniting with the gigantic Weasley clan, Harry builds the relationships he always wanted. And by the time the series concludes, Harry understands that family doesn't mean the people who are forced to (poorly) take care of him, but the people in his life that readily and easily put themselves between him and danger.
He Learns to Depend on Himself
Harry has always been brave and lucky since he was a baby, but by the time he faces Voldemort in The Deathly Hallows he has learned what Hermione always knew, that he, himself, is a great wizard. He figures out the secret of the allegiance of the Elder Wand, he faces Voldemort with no witnesses but Hagrid and the Death Eaters, and he knows enough to take his time before revealing that, like so many times before, he has survived to fight another day.
