I didn't start wearing a helmet till I was 30 (1 year ago).
Neither did anyone in my family (1 brother, mom, dad, 4 cousins, aunt, uncle, etc) and we are all still around.
It's their choice. Helmet laws are pointless IMHO.
I still think using a helmet is a good idea. I'm just not for our country's incessant desire to legislate EVERYTHING.