^ like mine! LOL. She's chunky (in the process of losing weight. Still needs another 10-15 pounds off IMO) out of condition, fuzzy, and in the middle of shedding.
OP, your mare has the general conformation that my own mare had at that age. My mare is a miniature horse. This is what I see- from the picture.
Straight back, steep croup, butt high (will likely level out with age. My mare was butt high until she was 3 1/2 and is still 1/2" high at almost 5. At this point it is a conformational fault), potentially over at the knees, posty hind legs possibly. Its hard to tell if she really has all of those faults with these pictures and at her age though. My mare grew out of some of hers, and aquired some new ones as she aged. Her back is a bit long and her front feet are in need of a very good trim as well.
Even if she does have all of these conformational flaws though, she can still be very useful. I wouldn't ever breed her but even as she is, if you condition her properly she'd probably do just fine as a lightweight cart pony. My miniature horse is driven regularely and is fine, although she has needed to be adjusted by the chiropractor once because her spine was sore (not because of driving, because of an accident involving a very high fence that she attempted to jump but didnt clear).
This is my mare. I would expect your girl to look something like mine as she matures. Just make sure that you don't ask her to jump or lunge until she is old enough to do so. I made the mistake of lunging my mare too early and because of that she became very unbalanced. I am just now beginning to ask her to canter on the lunge and she'll be 5 in about a month.
At your mare's age (actually a little bit younger..19 months I think. Just after a bath, she isn't sweating xD she was very...unfortunate looking.) Excuse her feet, at this point I did not own her and she was still a holy terror. No one had trimmed her in quite some time.
Again, still not mine yet and with poor feet. She's all trimmed up now ;) this picture is as a new four year old. Roached back (which your mare doesnt seem to have) but the rest of her flaws have lessened IMO with good nutrition.