The purpose you had at fifteen doesn’t have to be the one you have at twenty-five. It’s allowed to grow up with you.

A fifteen-year-old picked that purpose using the information a fifteen-year-old had. Outgrowing it is not betrayal or flakiness, it is what happens as you learn more about the world and about yourself. Holding onto an old answer out of loyalty to a younger version of you is a strange way to honour them.

Check whether your current direction is still chosen or merely inherited. Keep whatever is still true, drop the rest without any ceremony, and let the new answer be as provisional as the first one was.