When I started joining online transmasc spaces, I started seeing these older transmascs/trans men in their forties, fifties, sixties — there was one man who had started T at 63, I think, and it brought tears to my eyes to know I could grow up to be the old man I dreamed of.
Social media, mostly, but having medical resources specifically for trans men have also helped immensely. I like participating in medical studies just for the sake of solidifying science and medical practice in regards to transmasc folks.