I've been reflecting recently on the fact that I'm 24 years old now. (Eeek! How did that happen?) I was married at 20, had my first child at 22, and will have my second this year. It makes me wonder if people are ever tempted to tell me to "act my age." It's not the norm these days to do that so young; in fact, it's not the norm to get married at all.
Seeing our younger siblings contemplating marriage has been stressful for me. I want to tell them to back up and think about this more deeply: marriage affects so much of your life! I want to ask lots of nosy questions that they won't know the answers to yet, because they've never been in a situation like marriage before. I want to tell them to grow up more before they even think about making that commitment.
But on the other hand, I recognize that I probably shouldn't. For one thing, it won't do any good. For another, they would probably be justified in thinking it a little hypocritical of me. I sometimes look at my marriage and think, "Wow, I sure lucked out, because I didn't even think about whether Regis would be X or do Y. It's a good thing he is/does." And then sometimes I think that marriage is really a craps shoot, anyway: there's no way you can know everything about the person you marry or how their character and behaviors will affect your union, so you might as well pick your numbers as best you can and roll the dice.
I think marriage makes you grow up a lot. But I don't advise doing it that way.