I have been a firefighter/paramedic for 9 years. While I work in the south, have seen the result of people hitting their heads on just about everything but snow and ice. I'll spare you the details, but I can honestly say that after countless motorcycle, scooter, skateboard, falls, ect, ect. over the years I have never said "that dude was lucky he wasn't wearing a helmet". I can even say that a few times about seat belts, but never a helmet.
My father died of a traumatic brain injury about 3 years ago. After 4 months in a hospital where my whole family pretty much stayed by his side. Coming from a family member who went through this whole ordeal, I have to disagree that it's a personal choice to wear one. Ask your family. After a traumatic brain injury, they are going to be the ones dealing with your situation, you'll be obvilious. Maybe visiting you somewhere all the time, maybe if your lucky enough to go home - feeding you, bathing you, cleaning up your drool, stuff like that...involve them in your decision.
Sorry if this was a little over the top, but maybe it will convince just one of you to wear one and save you and your family from having to deal with something like this. Why is this in a fashion forum?