Crime rates are higher in Americans in their late teens to early twenties because peer relationships are most important in adolescence, as stated in the book "A Primer on Social Problems." A person's peers may commit crimes, which tends to draw others into the same activities.
Younger Americans lack full-time jobs, so the desire for income is higher – making crime a more viable option. Youth crime can also arise from relative deprivation. Relative deprivation occurs when one individual compares themselves to another based on some valued dimension, such as wealth or status,. Upon finding a discrepancy or inequality, the former individual is motivated to correct it through legal or illegal actions.
As Americans grow older, crime rates decrease. More people begin finding jobs and starting families, thereby increasing their conformity to social norms.