Elliot,

The folks who are truly at the top of their game in security first learn all of the fundamentals of operating systems, networking and so on. You just don't jump into security without a strong background. If you try, you'll sink faster than a rock.

That said, I would read up specifically on TCP/IP, operating systems, networking and then move on to firewalls, IDS and perhaps a scripting language or two.

Don't be afraid to jump into courses on these topics at a community college or even reputable trainers such as SANS.

Good luck on your adventure.

--TH13