Wise words from the waterslide

I was standing at the top of the waterslide behind an 8 yr old and his 4 yr old brother waiting for my turn. The 8 yr old instructed his younger brother on how to properly go down the slide and when he did, the older brother turned to me with a knowing sigh and said, “ah, they grow up so quickly,” before doing a belly-flop down the chute.