Pregnant mare bagging up

[Lifedaybyday]

I have a mare that isn't supposed to foal for 10 weeks and noticed a few days ago she is bagging up milk already.Still just clear when a drop is espressed.But tailhead is loose and buttocks are soft as well.
4 more weeks till she hits the magic 300 day mark.
Should I be worried?
Pics attached. Also seems enlonged vulva to me?
I think she will go early but at least want her to hold out 4 more weeks.I am almost certain there's no way she's going to make it 10 weeks.
She was preg checked by vet that put her the 1st week of September,and the previous owners date that she was supposed exposed to the stud lined up with the same due date.

 

[elizabeth.conder]

Can you get more udder pictures? From directly under is very helpful. Is she a maiden? Usually it’ll take at least 4-6 weeks to build a foaling udder. Some do it in less and some much longer. She definitely doesn’t have a “foaling” udder yet. But I would keep an eye on it. Can you also get a profile picture from the side and even with her so we can see how the foal is sitting?

 

[Maryann at MiniV]

Don't panic. She still has a ways to go according to her bag and the non-sticky "milk". She also is still a "wide load", so obviously not dropping.

 

[Ryan Johnson]

She looks great , though I would be watching her like a hawke.

If you look at the picture you posted , looking at her from behind, you can see the foal is not lined up ready for delivery. Once you can no longer see the foal "Riding wide" ( sides sticking out), the foal has moved into position.
Another thing that has always helped me is keeping a close eye on her udder. It will go up and down like a yoyo during the start of development. BUT when you see it stays the same throughout the day, you are getting pretty close.

good luck and ask away at any questions you have