You know, I skied almost every (winter) weekend from about age 7 until I went to college, and then several times a year after that. I never, ever wore a helmet, took a lot of nasty falls, and I never got hurt in the slightest. Looking back, I realize I was lucky. But nobody really thought about injury at all in those days and absolutely no one wore a helmet.
Foo, stay off the black diamond runs and you should be OK.
I will probably make a few token attempts at the easiest slope so that I can claim participation points, then go inside and drink hot chocolate.