Grats. Once you have a job with the government, it takes a pretty outrageous act (like murder) to even get fired. So unless you plan on murdering someone in the near future, you're good.
Congratulations on the new job =] The only job advice I have is to be friendly, be productive, and never EVER say anything negative about your coworkers (gossip has a way of spreading very quickly, but it's 100x worse in a government job). I'm sure you'll be fine.