Cee Ellis starts with a handful of questions and never quite settles on one answer. Why do people change? Maybe they grow up. Maybe they want to fit in. Maybe they change for someone they like, or for someone who didn't like them as they were. Or maybe they simply aren't happy with themselves. The speaker offers each possibility lightly, almost like thinking out loud, and the short lines make the poem feel quiet and unforced.
The turn comes near the end. After all the guessing, the speaker admits that the reasons don't really matter: "People change." Then the last line, "And we did," makes it personal. Until that moment the poem seems to be about people in general, but suddenly it is about a "we," a pair or a group that has drifted into something different. The word "we" hints at a relationship, though the poem doesn't say what kind. The mood is reflective and a little sad, with a tone of acceptance. The speaker isn't angry, just looking back and recognizing that something has been lost.