Harry Potter learned he was a wizard on his eleventh birthday, the 31st July 1991.
Be sure, wizards exist only in movies and literature.
There are a lot of bad wizards in Harry Potter, the most notorious being Lord Voldemort. He is often referred to as the Dark Lord by his followers and as You-Know-Who or He-Who-Must-Not-Be-Named by those who are too afraid to speak his name.
A half-giant named Hagrid breaks into a house where Harry and his aunt, uncle, and cousin are hiding. Hagrid gives Harry a smashed birthday cake, tells him he's a wizard, invites him to the wizard school, Hogwarts, gives Harry's cousin a pig's tail, and takes Harry away to get him ready for school.
Harry didn't learn anything from his encounter with the boa constrictor. He didn't know he was a wizard and certainly didn't know he was a Parseltongue. The incident did help to convince him that he was a wizard.
There aren't any there are only the discorvery points thing...
Azkaban is the wizard prison in the Harry Potter novels. As far as I know, it was never stated how it was formed; it was "just there".
It is not specified. You only know him as one of the three brothers who met with death.
I am so sorry that you do not know this and have not experienced the wonderful world created by JK Rowling, but, it is, of course, Harry Potter.
Yes, Japanese people do know about Harry Potter.
He's not. Harry Potter is not a nerd.
We don't know yet.
According to the Harry Potter series by J.K Rowling, Mud Blood is those people who do not know magic or do not belong to a wizard family.