I took a class in U.S. Womens History a couple years ago in college and kind of know what you mean. I'd work on concentrating on the material instead of all the people around you? Presumably you are in that class for your purposes and what you want to learn? Literally ignore the other people or try to get to know one or two before/after class so they don't all seem like strangers? Too, it's the beginning of the semester, it will probably get a bit better?

The other women are probably thinking about themselves/the material such that they won't particularly notice you (so whether you feel calm or not won't be noted, pretend you feel too hot or cold, it can probably be lived through :-) unless you jump up and start screaming? LOL