I'm fairly certain this was an anime. It starts off with an old high-level female mage with an eye patch who was basically the main hero of her nation. She has a small group of followers/students that she collected. One is a male noble type, definitely wealthy. The other is the male ninja type. The other is a male leader of a guild/group/faction. The other is a female woodsy type with earth-type magic.
They are all obsessed with her but she is old and tired, so she travels to her winter holdings, looking to die as she had lived a long life. She lays in her coffin and chants a magic spell, dispersing all her mana into the world to make it look like she died as her followers can sense her mana as she has the most powerful mana. Except her plan backfires, and as her mana disperses, she awakens as a young child.
As a child, she goes seeking the noble guy to help her set up a new life as she sees it as a chance to do all the things she couldn't do in her old life and makes him promise not to tell the others. In this life, she makes friends with twins or really close friends who are nobles. One is a boy and the other is a girl. Slowly she starts getting sucked back into the life of her past followers. And then we have flashbacks on how she met them and why they mean so much to her and why they are so obsessed with her.
One of my favorite stories was about the follower, who is the faction leader, was so obsessed with her that he would have his followers gather groups of people with her features and bring them back to his holding to soothe his soul, as the mage was the only one who could. Then free them at the end of the day with a big bag of coins. So he ended up picking out an old man from the group and placed her eye patch on his face sat next to him and complained and cried. But then an evil faction began to pose as him trying to use this rumor to do evil deeds, kidnapping people and hurting them.