Go for it! Careers are lame. Just do your research, like you appear to be, so you know what you're getting yourself into.
First off, you can always check out NOLS, they have various opportunities from internships to instructor training courses. Hopefully Mike Clelland! will see this thread and can give you the skinny on both what they offer and what being an instructor is like.
Various colleges (maybe your own) also offer outdoor courses and they have profession staff that lead many of them, or at least train students to.
I also know several folks who take on seasonal work like raft guiding or ski patrol, then do something like bartending or working at an outfitter during the off season. In my beloved home of WV, some people do both - rafting in the summer, skiing in the winter, shuttling between Canaan Valley and the New River. Jerks.
As far as at-risk teens go, it's not for everybody, but two of the best people I know have spent a good deal of time doing that. It was an ultra-commitment, but they loved it, and will tell you in a second that it has changed their own lives for the better.
Overall, I think you're looking in the right place when it comes to a job in the outdoors - instructing, guiding. From the subject line, I first thought you were wanting to be a sponsored athlete. Again, Andrew Skurka could tell you more about doing that than I could, but they are few and far between. There are probably something like 1000 other outdoor jobs for every 1 sponsored athlete. Heck, that's probably a generous estimate.