I think Stubali hit the nail on the head when he said "I haven't changed much". The changes happen so slowly we don't notice them. My sweet old mother, on here ninetieth birthday said to me, "In my mind I still feel like I was fifteen", To varying extents we all are the same that way. We can just close our eyes and we're the same as when we were younger. The problem is that others see us as we are now. They don't have the luxury of knowing what we looked like.
We need to realize that they aren't all being dishonest exactly, or if they are their fooling themselves too. Think about it, why would anyone do something that was definitely going to be found out immediately on meeting, and would probably be resented. The answer is that if they had logically thought it through they wouldn't do it. They believe it themselves.
Much as it is a turn off to the other person, and very disappointing, it's also find it kind of sad, a bit silly, kind of hopeful, and somewhat mad. It's maddeningly very human.

For the record I'm 66 y/o, my picture was taken 2 years ago, and I'm sure I look a bit older now.
But I hope not. Maybe I'll just close my eyes.