How do I counter age discrimination in my job search?

Getting screened out before anyone even talks to you is discouraging, and you have a right to be frustrated. You know you can do the work. The problem is that a number is being read as the whole story of you, and that is unfair. Naming it plainly is the first honest step. You cannot control other people's bias, but you can control what you put in front of them. The goal is to lead with what you offer today, not with a long timeline that invites assumptions. Show that you are current, energetic, and ready, and make the reader picture the person, not the age. Rework how you present yourself. Focus your resume on recent, relevant results, trim the earliest years, and show you are up to date in your field. Lean on the people who know your work, since a warm introduction skips the screen entirely. You may not change every mind. You only need the ones who are willing to see you.