I've been working (professionally) in this industry since I was 16 years old, I got my first job as a junior after tinkering with computers since I was 8 years old. At the age of 23, I've found it very difficult to earn the respect of the people around me because of my age.
I have the title of senior developer because I've had experience working on scalability issues and complex service based infrastructures, but many of my peers who are my age and recently graduated university and are still in their first junior roles often act like I haven't earned it - despite me graduating with a part-time degree in software engineering (okay, it's not computer science, but I'm still glad I did it.)
My point is that while age is generally a good indicator of knowledge and ability, it's not the be-all-and-end-all.