We get so hung up watching for amber gooh, we see it everywhere. lol. Looks like you've got a while to go, udder doesn't look near as full as it will be. Are you monitoring ligs? Is she making a nest? It is normal for the vagina to gape open a little. But, she's getting there! Good luck.
Have you watched the birthing videos on here and on youtube? Do you have your birthing kit ready? I'd also like to see an udder pic. While ligs are a good indicator...I watch for that udder to bloom...when you say to yourself "wow, that is twice as big as it was yesterday", that is a great sign that kids are coming soon. Do you have some exam gloves, I know clean bare hands are ok, (trim your fingernails) but I like the gloves.