"People did not know what she knew, that she was not really a woman but a man, often a fat man, but more often, probably, an old man.
The fact that she was an old man made it hard for her to be a young woman.
It was hard for her to talk to a young man,for instance, though the young man was clearly interested in her.
She had to ask herself, Why is this young man flirting with this old man?"