If you haven't already watched your child go through something serious, think about what that might feel like. Imagine them coming home or calling you with a pressing matter, especially if it's a situation you have discussed over and over with them.
I was a young mom, but I continued a lot of old school practices. I appreciated most of my upbringing, like my family's religious beliefs, morals and values, and overall mannerable way of life.
There were so many talks I did not receive as a child that I've tried my best to ensure I had with my sons.
You've spent so much time acting as your child's friend that they don't look to you for guidance and support. You're older, but you're no different than one of their peers.
There is a saying that many of us heard growing up, "I wasn't born last week." I seriously think our kids almost believe that or something very similar.