I don't have personal experience with white peas, but the consensus seems to be that you won't be able to tell the sex until they are quite a bit older...
Too young to sex them. The only way to find out right now is DNA sex. Other than that you'll have to wait until they're around 8 months. When they're that old you can post more pictures here. I ask now, when they are about 8 months get an up close, clear picture showing the detail of the neck feathers. You can sex Whites based on their neck feathers.