>>40770399 (OP)
never too old. better to troon out when you're john 50 instead of ending your life.
if you're talking about how old is too old to troon out and PASS, it depends.
after you finish puberty (the bulk in most people is done at like 16-17~) it's pretty much luck of the draw depending on genetics and how well you respond to hrt. at a certain point you start getting a kinda "second puberty" which in most people is around late twenties where you will masculinize even more and that makes it much, much harder. but even then I've seen people who started in thirties become passoids due to gigaluck