Under 16 is tough in general. You may want to check out volunteermatch.org or meetup.com for your area. My son's the same age and he's had the best luck showing up for general volunteer days rather than scheduled one-on-one events. If it doesn't completely clash with your worldview check out the local churches. They always have some kind of volunteer going on and most of the events around here are pretty secular.
I know this is late, and you're already working on a project. I just wanted to provide a good list of software that is out there for anyone's reference. I liked the Voglistics and Volunteer Impact when I was researching solutions.
Though it does not say so here, & 7 cups does have detailed safety practices on its web site here:
Hey. I'm a developer for the Point Cloud Library open source project, which totally community driven. We're currently looking for potential volunteers to help migrate your current website to Jekyll. If you feel taking the challenge, feel free to drop me a message.