Sometimes I feel embarrassed, because people see me, see that I’m female, and I worry they automatically assume I’ve got a rotting crab factory somewhere.

You can stop worrying, this never happens. Nobody is going around assuming people will probably smell like fish at normal social distances because of their sex. That’s not a thing.

Do people think vaginas in general might smell like fish, like if you go and stick your nose in one? Yeah, that’s a common factoid or comparison. But anybody who is looking at you and thinking of what your crotch might smell like at a distance of 2cm is not someone you want within 100m of you anyway.

If it really bothers you, take up some kind of smelly shampoo or perfume or something. Then you can know you are thought of as “the person who always smells like peaches” or whatever.