I think my first clue that I was irrevocably an adult was when I noticed that I was eating oatmeal for breakfast almost every morning for a couple of months. It should be noted that I hated oatmeal as a child and refused to so much as touch it. Almost all of my childhood food aversions have actually become foods I love. Except liver, that stuff is nasty.
I've always been the type that was only as mature and responsible as I had to be. If I could get away with goofing off, I would. When there was work to be done, that was fine, too. My dad somehow didn't pick up on this trait, and really worried about me when I moved out on my own. Mom, on the other hand, laughed and told him that I would be fine. And I was.
I never was in a hurry to grow up as a child. It just happened naturally and one day I'm eating oatmeal while working on the budget with Baby playing in the floor. What's more, I like the oatmeal, budgets, and my baby. Even if it does mean that I don't get uninterrupted sleep anymore.
Sometimes I do miss the time in my life when the thing I worried over the most was a chemistry test, but I wouldn't return to it now for anything. I'm sure not searching for the receipt to return my little son, moon, and stars. I'll take adulthood as it comes, and let my children take it naturally, too.
When I'm old and gray, though, I'm looking forward to scandalizing my grandchildren by blowing my straw wrappers at them.