You just started too late, and you're playing catch up - in my youth, kids falling off of bikes was considered normal. Hardly a day went by without one of us having some sort of crash. I used to keep count of the ones that were severe enough to require more than a week of healing time, but by the time I was 16, I had lost count. Falling is an important skill, and practice definitely helps. On the other hand, experience will definitely teach you how to avoid crashes better than any other form of study. These days, I seem to lose my vertical orientation less than once per year, and I still learn something every time.