Don't get hung up on the age of which you decide to make career shifts. I'm 27 years old, joined the military at 19. In just a couple short years I'll have 10 years of service in (half way to retirement) yet I'm going to be separating entirely to start a new career. Most people think I'm crazy for it, but I'm not happy with what I'm getting from the military anymore. I know lots of folks who have had career changes in their 40s and 50s. If you manage your finances correctly, you can do so much more than you'd imagine.