Marellus, N.Y. — Not being good enough. These are the words that high school sophomore Ava Morey Farley wrote on a rock with a Sharpie to represent what’s holding her back. “I have abandonment issues.

The sun filtered through the trees on the brisk, December day as I stepped on to the Montgomery Whitewater ropes course, where ropes and ziplines created what looked like an interconnected system of ...