I was lucky as parents started a rafting company when I was 13 and I was pro guiding by 14. In the winters I surfed and backpacked (grew up on CA coast). Wrestled freshman year in high school but quit to surf more (oh yeah, and wouldn't cut my long hair - coach didn't like it). Did some low grade rock climbing too.
Started kayaking in high school because lots of other raft guides were doing it. Quit at 18 (kayaking, not rafting) because I moved to Grand Canyon and there isn't much kayaking in the off season there. Started kayaking again in early 40's. Now 53 and never plan on giving it up. Still rafting too occasionally.
Other sports/activities as an adult: skiing, snowboarding, martial arts, along with yoga and (very) recently weight lifting.