If you think your career is finished at 30 you either don't have the technical savvy to succeed or need to get a little self confidence
I'm a 29 year old non-OS programmer who is learning Linux device drivers. My boss didn't ask me to learn it -- I told him I had to in order to continue doing my job. Get some textbooks, create a test/development environment you can use where you won't break anything, and go buckwild.