Do not become someone your younger self would have needed protection from.

Who you were at fifteen would have had a clear reaction to certain kinds of adults. It is worth occasionally checking whether you have drifted toward being one of them: dismissive, unkind to someone with less power, casual with a promise made to someone young. Drift like this happens gradually and rarely announces itself.

Bring that earlier version of you to mind and ask how you would look through their eyes in a specific recent situation. Not as a judgment on your whole life, just one situation. Where the answer is uncomfortable, that is a place to adjust, and one adjustment is enough to start.