A few months ago, I went to a briefing hosted by the Girl Scouts. I was impressed with some of their work, but disappointed their platform for speaking to girls in the US: "I always tell them how lucky they are." I find this disturbing, because it's all relative.
In any event, I do know that some chapters of Girls, Inc. do great things, and there are also likely local initiatives in your area—perhaps through Women's Way or another women's organization. In New York City, there is something called The Girls Project, which is great, and also the Lower East Side Girls Club, which runs a cookie academy. You sound motivated enough—I might recommend that you start your own thing.