"That was always the dream, wasn’t it? ‘I wish I’d known then what I know now’? But when you got older you found out that you now wasn’t the you then. You then was a twerp. You then was what you had to be to start out on the rocky road of becoming you now, and one of the rocky patches on that road was being a twerp.
A much better dream, one that’d ensure sounder sleep, was not to know now what you didn’t know then."
- Terry Pratchett, Night Watch
The first time I read this quote, I took it at face value, and agreed. The older I get, I watch my stepson grow up, he'll be 20 in less than 2 months... I see him being a twerp. But the change is that now I think the meaning of the quote is a little different. Today, it's a way for me to temper my reactions to his missteps. He'll grow up, assuming I did my job right, and stop being a twerp. And with any luck at all, he'll recognize just how big of an asshat he actually is right now, and wish at some future time that he hadn't been.
Same goes for your granddaughter, FR. Good luck!