Heh. I was 46, a few months into transition, and just at the tail end of my androgynous phase when I went to a liquor store I hadn't been to before. The guy carded me, and I reluctantly relinquished my ID, which had a male name but a female marker. He looked at the ID and back at me and back at the ID and back at me...didn't look at all happy but let me buy the booze. But I felt so conspicuous that I tried a different store the next time.
I figure he read me as male at first and then saw my age or the F (or both) and was trying to figure me out. Ugh. I hate feeling like a bug under glass.
I know that I've been lucky because that andro phase didn't last for very long after I started T, but I actually think that middle age has helped me to "pass" better. I might not have looked my age, but I was no longer a fresh-faced youth, either. A few grey hairs and a few character lines can go a long way toward making a newly transitioned guy look more manly. Of course, there are too many little factors to fully account for, and they all add up in different ways and vary from guy to guy. It's all rather mysterious.