It looks like her udder has squared off a bit. I think it will do more, ( just because she has had this udder so long with out foaling) But I could be wrong too... Let me show you a pic of Kate when she goes BOOM. She always foals after the BOOM, and your mares udder reminds me so much of hers. ( course each mare is different!) And its possible Pandora will foal on the udder she has!
First is Kates in the almost ready( teats still touching, like Pandoras) ,second is the BOOM Teats separated.