We’ve all seen them: little girls wearing blue tunics or vests, brown sashes, sometimes green hats and skirts. They stand in front of banks and supermarkets and hardware stores peddling their brightly colored boxes of deliciousness. The price has gone up, again, and though what the girls sell is addictive and only available once a year, it’s hard to justify spending that much on cookies. But we should. Here are three reasons why. 1.) We’re teaching today’s girls to be…