Many others have observed that a seemingly disproportionate number of "mature" people are active here, and I have read articles noting that a growing number of mature adults are coming out as TG, and some as TS, and transitioning. Naturally, we wonder why. Perhaps it's is nothing more than a reflection of society's greater openness -not an absolute or even a proportionate increase in numbers. Or perhaps its pent up demand inflating the numbers momentarily in response to greater tolerance.
My guess is that both may be contributing, but I also suspect that more mature people are better informed about themselves, even as the greater society has grown better informed and more tolerant. Having access to good quality information, primarily via the internet, as well as access to competent professional, support groups, discussion forums like this one, and even mainstream media, collectively are dispelling long held and deeply ingrained beliefs matures had about their gender identities, and opens us to possibilities we once assumed were out of reach.
I suspect there is one more factor. Once one abandons the old stereotypes and evisions new possibilities, perhaps we have a desire to make up for lost time, knowing time is not on ur side. The days grow short... and you haven't got time for the wailing game... as that old song reminds us. So, perhaps we want to enjoy these September days while we can realizing long denied or suppressed dreams.