Down through the ages, a traditional form has evolved for this type of speech, which is: Some old fart, his best years behind him, who, over the course of his life, has made a series of dreadful mistakes (that would be me), gives heartfelt advice to a group of shining, energetic, beautiful young people, with all of their best years ahead of them (that would be you).
And I intend to respect that tradition.
Now, one useful thing you can do with an old person, in addition to borrowing money from them, or asking them to do one of their old-time “dances,” so you can watch, while laughing, is ask: “Looking back, what do you regret?” And they’ll tell you. Sometimes, as you know, they’ll tell you even if you haven’t asked. Sometimes, even when you’ve specifically requested they not tell you, they’ll tell you.