Wear the helmet!!! My son didn't and was hit by a car, in a coma for three days; not good. 8 miles is nothing, I'm 61 and ride up to ~25 miles on the weekend; yes I wear a helmet.
Its great to hear that you are 14 and playing golf, keep it up, it provides more benefits that you realize. You'll meet great people who can help you throughout your life. If you go into business you'll be able to network on the course. I play in the company golf league and I get to meet and network with a lot of people I work with. Its a great sport.