A 15-year-old would be in their fourth year at Hogwarts School of Witchcraft and Wizardry.
Here's why:
- Students begin Hogwarts at age 11. This is established in the first book, Harry Potter and the Sorcerer's Stone, where Harry, Ron, and Hermione are all eleven years old when they start their first year.
- Each year at Hogwarts corresponds to a year of schooling. This means that a student who is 12 years old would be in their second year, a 13-year-old would be in their third year, and so on.
- Therefore, a 15-year-old would be in their fourth year.
This aligns with the events of Harry Potter and the Goblet of Fire, where Harry, Ron, and Hermione are 14 years old and in their fourth year.
