The art and science of child rearing

I've been known to be naive on some topics. I actually thought child rearing ended when they turned 18 and went off to college. When my dear son Nick turned 21 and was still living with me and going to school, I realized that was a myth. Sort of.
Nick is 23 now, and he's a man. But I still feel responsible for taking care of him. He still needs my help now and then.
Anyway, my two beautiful children 23 and 11, yes 12 years apart are currently engaging in a traditional sibling practice. They tattle on one another.
Now, I get that siblings do this. I have a sister 2 years my junior. BUT I also have a brother 10 years my junior. My sister and I sibling rivaried 'til we dropped, but my brother and I -- NADA. I would never have thought to compete with Tony for anything or to tell on him. It would have been ludicrous. Maybe this is because I was out of my parents' home when I was 18...probably.
So here I am in a different place in time, and my mind is boggled.
Recently my son broke a precious bowl of mine. This bowl had been moved several times and carefully treasured for years and years. He left it on the counter in its broken state, so I would know it had happened. Afterall, he's 23 and a good kid.
But when I returned home that night, his little sister, my sweet 11-year-old daughter, Claire, leapt to tell me that Nick had broken the bowl. She actually seemed to delight in telling me, and when I asked her why she tattled, she explained that Nick would not have told me... which was kind of more than a little amusing because he so obviously left it out for me to find.
OK, so this was not all that strange coming from an 11-year-old girl. But this is where it gets kinda twisted. Two days or so later, I get a call at work from my darling boy. He wants to inform me that No. 1, he's doing dishes, (which is very cool) but No. 2, his sister has 9 -- count 'em -- 9 dishes in her room and 7 plastic drink bottles in various places throughout the house.
At this point, I am stifling my laughter and trying to explain to the young man that 11-year-olds are slobs. REMEMBER????
Nick goes on to tell me that he has piled these things on his sister's bed and is of the opinion that I need to come down on her in a strong manner, so she learns her lesson and doesn't turn out --- like him.
I am so delighted that they are acting like siblings. When I had them 12 years apart, I feared they would never really know one another and never have the issues that siblings have and that I now look back on fondly from my own childhood. So for me this is an amazing and delightful part of life.
I hope they grow to treasure one another and understand that this time is brief and fleeting and all that gushy mom stuff, but more than anything what great free entertainment!