When your parents repeatedly gave you good advice, and you traditionally ignored it.

Haa! I'm old, hopefully your kids discover this secret before they enter college, because they will love life so much more if they do, because parents are the most legit people ever.

One is getting close, 16! My mother used to say, "Don't worry about it! They won't graduate high school (wetting the bed)!" <---insert your own there>

Oh wow, not far off at all! I'm an undergraduate right now, and without mental preparation, college will devour your soul and empty your wallet. Tell your kids to get used to planning their homework and responsibilities on a calendar, because I don't do it, and I will regret that later.

College Kills

FR FR :OP

They'll figure it out eventually. If I can figure it out, anyone with a brain stem can. :D
How about your other kids?

They will persevere, I know it. I don't know it, but I hope I know it so that they will persevere.