This study examined in a random community-based sample of 664 12-19-year-olds, the relation of subjective experience of age (SEA) with chronological age, dating experience, sexual activity, and substance use. The results revealed a positive linear relation between SEA and chronological age: individuals who were chronologically older felt subjectively older than their actual age. Several possible sources of interindividual differences in SEA were identified. Adolescents who were dating an older partner felt older compared to other dating adolescents. Sexually experienced adolescents felt older than their non-experienced counterparts. Smoking (in boys), higher alcohol use, and higher drug use were also related to an older SEA. These results suggest an increasing discrepancy between SEA and chronological age across the teen years as young people experience the normative changes associated with adolescence. Dating, sexual, and substance use activities may figure importantly in the way that adolescents experience their age.