I respect you for querying and gaining perspectives on this subject.  Before I go much further, though...  (don't take this negatively, as that's not the intent.)

Do some digging on the forums (use the search, and even Google on it, using a site:ethicalhacker.net search.)  This is a topic that there are already a LOT of posts and threads on here, about.  If you exhaust those in your research, THEN I'd be happy to add some insight.  But part of doing what we do (pentesting / security) requires a lot of research on your own, and I can promise you, a bit of that, here, will yield you much of the info you're after.

Let us know if you need further help, after you dig.  There are many here who can help you continue to grow, and I'll be happy to contribute.  Biggest thing is, I'm a firm believer, as are many of us, that there/s no point in repeating the same information, over and over, when it's already at your fingertips!  

Good luck, and happy hunting!

If you're in school, a good option would be a college job with the CS department working with the Sysadmins. I'm a bit biased since I am currently a Sysadmin, but they're the ones in the trenches and you'd get good work experience in addition to some extra money in your pocket. If there aren't any college jobs available, you can always volunteer your services. Most college campuses I've been to don't have all the resources they could use...

Good luck!