Is it Possible to Age Yourself Out of a Job?

An anonymous reader asks: "I'm a programmer with more than twelve years of experience. In all that time, I've never been a 'senior' developer. I'm competent and I work hard, but I don't think I am quite a senior developer in terms of technical or people skills. More and more I feel that I'm aging myself out a job. By this time, employers expect someone with my experience to have advanced some, and they may not be willing to even talk to me now, thinking that my pay requirements have grown while I have not. Even if I did get hired someplace new, my peers would likely be much younger than me. What do you do when you have an applicant like that? Are my fears legitimate?"