That's a steal for a Borough bag, but I wouldn't assume it went for less than she wanted until she says something that would make you think that. Generally if that happens to a seller, if they don't want to sell it they will message saying they 'lost' it, or already sold it, or don't want to sell it. It happens, I get that.
As for the shipping, today is the 9th, right? Correct me if I'm wrong, but that makes today the 6th business day after I subtract the holiday. Given that you paid right away, and the shipping info says the estimate includes handling time by the seller, I'd consider this buyer out of line. As someone who has never given negative feedback, this would be an uncomfortable situation for me.
I hope she gets back to you soon with some sort of info so you can stop stressing.
Even with a holiday, as a buyer, if I pay right away, I don't expect 9 days+ to be considered expedited in any way. If she sends the bag, you can look it over and make sure you're happy and decide on feedback then. With the steal that the bag is (imo) I'd probably still be happy overall, but it's still frustrating.
I wouldn't assume though that just because she posted the number that it's only a glitch and she really did ship it. Most of the time when that happens to me, the seller really hasn't shipped yet, just printed a label. I have yet to see something else happen on my end or for a seller to explain it that way.
Again, hoping the best for you! I'm sure you'll get the money back if it doesn't go through, but I do hope it's on its way soon. Keep us posted!