A/N: I'll keep this brief. I don't own anything. It all belongs to Ms. Rowling and her publishing house. Anyway, thank you and enjoy!
When he was five, he wanted to be a fireman. Uncle Vernon seemed to approve of it, since you didn't need to go to college to be a fireman. Less money out of his pocket.
At seven, when he wanted to be a doctor and shared this view with his Aunt and Uncle after Dudley got a bloody nose, Uncle Vernon started laughing and told him that there was a better chance of broomsticks flying and owls becoming carrier pigeons.
One the first day of his first year at Hogwarts, he decided that he wanted to one day become the Headmaster at Hogwarts. He had no clue what this entailed at the time, it only being his first day, but as he looked up at the great man in the center of the staff table, he knew that this is what he wanted to be.
In third year, when Lupin was teaching him how to cast a successful Patronus Charm, Harry decided that he wanted to be a Defense Against the Dark Arts professor. After all, what could be more fitting than teaching future children about his favorite subject? That is, if Professor Lupin had no objections to stepping down, obviously...
In fourth year, when Moody mentioned that Harry would make a good Auror is when that seed of an idea was planted. He began to wonder. Would he make a good Auror?
By fifth year, when Career Advice Meetings were going on for fifth years, he actually began, for the first time, to think seriously upon what he wanted to be. He kept coming back to Auror. Despite the origins of the idea, he could think of nothing else in the world he wanted to be. After all, he was getting training students in Defense Against the Dark Arts already in DA. That pretty much proved to him that no matter how rewarding teaching was, he was not cut out for it. When Umbridge protested that he would never become an Auror, it spurned him on even more. He had to prove that vile, frog-like woman wrong after all. And McGonagall sticking up for him didn't hurt either. He had decided, an Auror is what he wanted to be.
After what would have been his seventh year, he discovered that Minister Shacklebolt had given permission for all who were involved in the Battle of Hogwarts to become Aurors without completing the usual qualifications. Given his past year on the run and the subsequent squashing of his dreams that this had delivered, he was quite pleased. Once again, he made up his mind. He would be an Auror.
And here he was today. As he stood next to Ron and Neville, clutching the coin Hermione had made for Dumbledore's Army, he became an Auror. He looked at his two friends on either side of him. Both were grinning from ear to ear and he knew that it didn't matter what all of his past goals were or what anyone else said about his current goals. All that mattered was that right now, in this moment, Harry James Potter became an Auror and not only proved Dolores Umbridge wrong, he proved to himself that yes, he could achieve whatever he set his mind to. Defeating Voldemort aside, this was the greatest moment of his life thus far.