She's a lovely looking little mare - hard to see her conformation from such a diddy pic, but she looks good from what I can see! Do you mind me asking what stally you've chosen for her?, I'd say a nice compact TB or arab would go very well with her to get a nice small competition type - they really are like hens teeth now as everyone is going for the big warmbloods and breeding huge things!
I'd definitly ask your vet about the embryo transfer - you can freeze a few then too, so if this foal turns out well you have the chance of a few more, and as your mare will not be out of action the more stuff she carries on doing and winning the higher the value of her foals.
With pony type mares they do tend to have a longer breeding life than the larger breeds, I've seen ponies and pony crosses breeding well into their twenties so with careful management and a really good level of nutrition and high quality forage it is do-able.
If this is your first foal do read up loads! - just be careful if she does have a foal even the most friendly of mares can turn agressive understandably when they have a foal to protect - so I would advise against playing games with her - or the foal as you'll get smushed!!!

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