Someone has died on his maiden voyage because he slid out and nailed a curb with his skull(no helmet). Others have been injured by having crappy brakes in an emergency stop, when someone pulled out in front of them...
Some have been injured just by the pure idiocy of drivers on the road.... "oh I didn't see you, I was texting... Sorry I ran you over"...
Others still have been injured by not realizing the speed at which an engine will carry you, whether by inferior components, fender mounts disintegrating, idlers rotating into the spokes at speed...
There are many number of ways to injure yourself if you do not respect your machine, yourself, and/or traffic in general. Helmet is a must, lights after dark are a must, and proper maintenance is a must. eg. make sure mounts are snug, lights are working, etc...
Don't be scared off, just take the proper precautions... and ride like you're invisible.
Best of luck, and don't be afraid to ask any question, no matter how inane. But... There is a handy search box up top(just so you know)