I have to say I do take offense to a couple statements made by the original poster. Such as
Ponies are stubborn bitches. That is why we bought a mini. =]
I have been breeding, training and showing American Shetland ponies for years and they are not stubborn bitches. They are very smart though and you can train them a bad habit as fast as you can train them a good one if you don't know what you are doing :)
I also breed, train and show American Miniature Horses. I have never asked 7000.00 for a broke mini :) Not even close. I do however always recommend to people to buy a GELDING for kids to ride verses a mare. Geldings just make better kids horses as there are no hormones to deal with.
At 41" she is a grade pony. I will probably get flamed but you are fine to get on her for a few mins at a time to be sure she knows what is being asked. This is done all the time with ponies. I also believe in using sand, long lines etc but at some point a human has to get on the horse. I would rather it be a small adult then a child.