Started at 55, now 59. Asking these kind of questions for the past 4.5 years. During most of my life, I simply didn't pay much attention to my thought processes regarding gender. Then at 55, I took a temporary job away from home, I was away for 6 months and that's when these things surfaced. Too much time on my hands for experimentation and self-contemplation.
I believe hormones also play a role. Looking back at my life, I know that I have always been borderline masculine. I was not interested in sports, didn't really hang out with the guys, liked singing and playing piano, enjoyed crafts (sewing, knitting, Christmas decorations), didn't like war or the military ... and the list goes on. If I stand back and take an unbiased look at this person, I might wonder whether this is a guy or a gal we are talking about. Fast forward to mid-life and the T starts it's natural and normal decline. At 55 there is opportunity and motive and suddenly my life is turned completely upside down.
Had I not taken that job, it's possible that all of this would have been delayed or perhaps not experienced at all. Can't really say since "I took the one [road] less traveled by".
Now as to my current status and thinking; with a different mind set, I would probably go the whole route and try to live the rest of my life as a female. However, my spiritual background and present mindset has given me a unique perspective on life and it's purpose. Hence, I choose to find my own place and the gender realm and live life on my terms. I was born with a male body, I will end this incarnation with that same, unaltered body. However, I will be consciously be doing, going, wearing things very few other males would consider or even want... I will be my own person.