crossing any urban street on foot is dangerous. riding a bike in traffic is dangerous. driving a car is dangerous. flying is dangerous. looking at those jersey guidos is dangerous. etc, etc.
sure, accidents happen...but not trying any of it out of worry is just plain sad. prepare well and have fun!
you've already gotten excellent advice about what and how to descend safely. helmet, brakes, well-tuned bike, technique. feather the brakes if you need to in order to find out what's comfortable for you. i routinely break 50mph on a 15-year-old italian steel bike...absolutely worry free.