They're going to have far more interesting things to talk to their friends about than your family finances. Trust me!
I never knew how much household bills were when I was an early teen or before I left home. I learned quick because I got married at 21 and then DH and I had to sort out a mortgage and budget for bills.
With my DC, I was very open about finances. About working, essential bills when you leave home, budgeting, how much everything costs, utility and council tax wise, food, petrol, insurance - all costs realistically.
I did this along with other life lessons such as cooking a meal each week, washing up, changing their bed, taking the rubbish out.
What favours are we giving our children if we don't guide them into adulthood and responsibility without understanding economics, living, and taking care of yourself?
I'm 52 btw. Not completely out of touch. And I'm soooo proud of my DC.