"Maybe I’m a bit maudlin because my own teenagers just turned 17"

I'm betting your kids are in better shape going forward, than that building, thanks to you.

Of course it's going to hurt letting go a little, as it has been for every good parent who has ever lived. You are part of the great tapestry of life, the way it has always been and the way it will always be.

Luckily, you have at least one great positive fun hobby, in Steemit, to fill some of the hours you once gave them. Maybe try to get them on it too.

And hurry to do the things you love to do, cos sooner than you think, the years will pass, and you may find yourself a grandma, being asked to do all those many many things grandmas do lol. ;)