You're right. Studies have shown over and over that back pain is more common the older we get. Some of this is the result of aging, spine degeneration, and the arthritis that comes with both. But other studies also show that teenagers and young adults have a fair amount of back problems.
Between 30 and 40 percent of people under 25 years of age report mild back pain. Almost 90 percent of this group has more back pain later in life. The peak years seem to be around ages 40 to 50 and again between ages 70 and 80.
Finding ways to prevent back injury and pain is the focus of many studies right now. Keeping active, stopping smoking, and maintaining good balance and coordination seem to be the key tools in this effort.