She looks pregnant to me!
My arabian dandy (avatar) was 20 when she had her very first (and only) filly! It was an accident. We had gotten a stallion whom was very, very calm and didn't act like a stud at all. However, we did keep the separated and such. Our mare flirted with him through the fence, but he was never interested. Well, I suppose he did get interested one day when we weren't home. It was a wooden corall, and he wound up knocking the middle post out and breeding her through the fence. His name, Rebel, should have tipped us off when we bought him lol
My dad and I were very worried because she was older and this was her first. However, she did just fine. We took her to a friends barn because it was January when she was due and we didn't have stalls, just shelters.
Here are a few tips from my experience. I've only gone through this once though, so please anyone that finds my information wrong PLEASE correct it!!
I was able to feel or look at my mares belly when she was close to having the foal and actually see the foal kicking inside. Like just behind where her ribs end on the side there infront of her back leg in that area.
I've heard that horses usually go into labor either late at night or early morning. This was the case with my mare, she had Sasha (her filly) at 11:45pm. So make sure you check her at night aswell! I spent two weeks at my friends house so that I could check her throughout the night haha However, I'm sure mares do have them in the day aswell!
Some of the signs that they show when they are close would be: pacing/restless, looking back at their stomach, maybe laying down and getting back up, and sniffing the ground (Dandy showed these signs the day she had Sasha)
Also, her teats were hard and waxed up a few days before she had Sasha. Their teats get this white/cream looking drip of wax on the very tips of their them. This is a sign that they are getting close aswell!
If she does start going into labor, try to remain calm. I've heard you can actually stop a horse from having the foal if they start getting too stressed about what's going on around them.
I suggest looking up complications a mare can have when foaling. Especially if a vet may not be available! An important note though, if you do have to help pull the foal out. ONLY pull when she has a contraction!!!
Have plenty of clean towls available, you may have to clean their nose off a bit so that they can breathe. (We did with sasha)
I hope these are helpful to you! To me, it looks like she may have a couple weeks to go? My mare looked like that, but about a week before she had Sasha her stomach kind of dropped and got really wide. I also agree, try to find an experienced horse person to help you out! If you don't already have a stall, maybe try finding her a place that you could board her at for these next couple of weeks. That way she's in a nice clean stall and there should be someone there to monitor her aswell for you. Plus, you would most likely find some people experienced with foaling. My friend that let me take my mare to her place is very experienced with foaling. She was a trainer/riding instructor and had many, many foals in her life time and let me tell you, it sure made me feel good to have a person with extensive knowledge in the particular area by my side!!!
Please keep us updated and I wish you the BEST of luck.