If you really want to get constitutional on it, I think a better angle might be 4A (unreasonable search) or 5A (due process). Requiring disclosure of my age is

If you really want to get constitutional on it, I think a better angle might be 4A (unreasonable search) or 5A (due process). Requiring disclosure of my age is effectively a search, without specific probable cause, and there are no means for me to challenge this in court.