Windsurf? At your age? Why not? It’s a sport that only requires an ability to swim, a sense of balance and not massive strength. Especially if you take lessons where the Bay waters are warm and the wind velocity not overwhelming. Boardsports has 2-day classes at Crown Point Beach in Alameda and Coyote Point Park in San Mateo for $165 for 2 days. Cal Adventures in the Berkeley Marina charges $95 for 2 days.