Age vs career in natural science Due to my country's education (we finish high school later than other countries), a year off, doing master's degree, I am finding myself in my first year of PhD in States   being 26 years old, possibly graduating when I am 30. I have recently become very anxious about my age, since scientific career has been always my goal, I feel like I am too old and behind everyone else. In Europe, where I am from, I have been told that age does not matter as much, and what matters is papers/scientific output, especially since the end of PhD, in support of me pursuing the doctoral degree in USA, where it takes longer. I am doing my PhD at one of the top tier schools in a very prolific group, where I am surrounded by people that got their PhD when they were 25... 
In addition I know from experience of me and others that in my field (physics) women are heavily biased against at all stages. Also, my field requires completion of usually 2 post-docs before applying for positions, which would take around 5 years.

I am looking for some input on this and how realistic  my chances of staying in academia are, how much age matters when hiring for post-docs/faculty positions (in Europe) and how to cope with age related anxiety in academia.
Probably, age at graduation is not the most important factor for a career in academia. But assuming it was, then according to your estimate (30), you should be rather competitive.


  For the 2003 doctorate recipients, the median total time from
  baccalaureate to doctorate was 10.1 years, while the median registered
  time was 7.5 years and the median age at doctorate was 33.3 years.


Time to Degree of U.S. Research Doctorate Recipients 

(Being 33 and just about to submit my thesis, I'm right on target.) Also notice that with your pre-PhD degree, you are already looking back at a  a few years of scientific education that your US peers lack, if they start grad school with a bachelors degree. Academic employers know this. 

Maybe this is not a full answer to your question, but at least a consolation. Don't panic.