Negima! (2005)

Negi Springfield is only 10 years old, but he is trying to become a wizard(Magister Magi) but he was sent to Japan for training, despite the protests from his sister. The principal, who was a friend of his grandfather, assigned him to be the homeroom teacher and English instructor of middle school which is an all girls school. And the class is full of girls, with "special" characteristics, like one being a vampire, another a ghost, another a robot, and others being athletes and bookworms. Negi puts a lot of good will towards everyone and works hard to teach them, and even though most of the girls are very friendly with him, they see him more as a kid to have fun with instead of a respectful instructor, except a few of them, that hate the concept of him being a teacher, one of them is an anti-social computer nerd and the other is a hard worker who had a crush on the previous teacher, and to make matters worse, she found out about Negi, and his magic. Think of it as a Harry Potter meets Love Hina meets Azumanga Daioh meets Sensei no Ojikan Doki Doki School Hours, except picture it in a middle school.