Squeezed at both ends! At some point I passed from too young to too old, but never got to enjoy the supposed middle period. I remember the struggle of trying to prove myself during my early career and then suddenly found myself in "mid-career" and being pinged by recruiters for entry level positions.
Noe, despite my self-confidence, articles such as this make me uneasy for the future. I don't really want to "graduate" to a management job. I love writing code and solving problems. I just hope there will continue to be enough level-headed hiring managers to let me do the job I love.
We say three years plus for senior engineer. We have people with that experience who are fantastic software engineers and completely deserve the title. You don't need 15+ years of experience to be a good engineer, but it helps.