One comment I'd have is that a large fraction of the admins I know had an experience in their career where they got thrown in way over their head and they had to learn under pressure. One of my mentors worked at a large bank, and 1 month after becoming a Unix admin the senior admin quit so he ended up in charge of hundreds of workstations and servers by himself.

In my case, 1 year after getting into Unix I was hired to be the middle person of a 3 admin team for a fairly small company. There was supposed to be a very experienced admin hired for the senior position. The day I showed up they told me the senior guy got another job offer and wouldn't be joining the company. So day 1 I ended up in charge of the entire Unix environment for a new company I'd never worked at before! Not long after that, due to layoffs I ended up the only person between both Unix and Storage teams, doing the work that was handled by a team of 6 about a year earlier. It was tons of work and stress having to come up to speed that fast and handle everything on my own. But for the long range career outlook it was great. I had experience and knowledge I never would have gotten working under a more senior admin again.

So, I guess the practical advice for you is to find a way to work on Unix, even if you think it's beyond what you can do. If you truly love it and have the talent and smarts it takes you'll manage to get by and learn more than you ever could reading books. Find a part time or entry level Unix job, or volunteer at the church/school/charity of your choice to work on their Linux or Unix systems, or somthing like that. Find a way to get real world experience even if it seems intimidating at first.

Good luck.