If you can get a gov job, definitely go for it. When I finally thought about applying for gov job, I was already too old. The great thing about gov is not just the pension, but also the post retirement medical benefits. If you are someone of modest habits, a gov job is great for your future.

I think the age limit is around 30/30+? If that's the case, you can still work in the private sector for a couple more years and see where you're at. Who knows, maybe you'll be a highly paid manager by then. If you feel by then that you'll always be a regular salary-man, then you should try to go for gov. Just know that promotion prospects might not be high if you don't meet certain qualifications.