Not folk songs, but here's what I could think of:

Diana Ross (wasn't it?) sang that "My momma said, You can't hurry love..."

Tracey Chapman sang "My momma told me, cause she said she learned the hard way, said she wants to spare the children: All that you have is your soul."

In the song "The Real Love of my Life" from the musical Brigadoon, a father urges his daughter to find a boyfriend and gives her advice on the prospects she comes up with.

Marion