When she was in 7th grade, Heidi Li and the five other members of the Oyster Gardening Club cultivated hundreds of oysters to help repopulate the Chesapeake Bay. On the day they released the oysters into the bay, the event attracted TV journalists and local officials, including the governor. The attention opened the young Li’s eyes to the ways that a seemingly small effort in her local community could have a real-world impact. “I got to see firsthand how we can make change at a grassroots level and how that…