Good cycling shorts with padded chamois....if you aren't already using them. Much better than a Kotex - last longer too!
No underwear under said shorts. Undies can move around and chafe you.
If your saddle doesn't have a cutout, you might find that a saddle with one is more comfortable - especially in the front. I use cutout saddles and never have any numbness or pain in the girly bits. An inexpensive cutout saddle you might want to try is the Performance Women's Contour. It might not be "the" saddle for you, but it's not a big investment, and might let you know if a cutout works for you.
Finally, more time in the saddle will help as well. Your sitbones require some toughening up when you first start riding. But your girly bits should not - you need the proper shorts and saddle to keep that area from hurting. They shouldn't hurt even from the first ride, and won't with the right saddle and shorts.
Good luck to you, and welcome to the world of cycling.
Emily