Not in Germany. I started studying at 18, so as early as possible. Finished after 5 years with my Masters degree. A PhD would've taken a minimum (!) of 3 more years, so I would've been 26 or older. If you don't have a perfect start, take more than regular study time or take longer than those 3 years, it's easy (and not considered being bad) to be 30 when you're done.