Well the farrier saw her and laughed at my concerns. I feel silly but have learned a lot so that's ok. I still have almost a week to go before the vet sees her but they usually say close to the same things. I found this vet through my farriers recommendation so that's not surprising. Our farrier is wonderful and I've always found his advice to be good for us and our pony. I think I might see a different vet at least once to look at their teeth. It sounds like this is a good idea anyway just to have more options in an emergency.
The farrier said a little rib showing is often seen in horses that have been trained for...I don't remember the word he used. Highly trained for work though. He said that will fill out just from her easy life now and that she was probably sold by the original trainers because she wasn't good enough at this work. He said she looks fit and healthy.
Then he told me I should have gotten a gelding not a mare for an all the time safe horse, but on this we agree to disagree.
I've never owned a gelding and what he says makes sense, but we all love our little mare pony and with regular work she stays very nice and safe. She's only pushy when we come back from vacation and it only takes a little work for her to be sweet again. Her companions have been a couple of goats and she has to be pushy with them. Hopefully my preference for female animals will be ok in this.
He says we need to have an adult ride her off our property as well to keep her training as good as now. My daughter has always done bareback on our property as it helps her own muscles and balance, with some lead-line time off property. We live on the edge of a national park so I and my oldest can schedule some riding time with her there so that should be ok. My oldest is very happy with this and we can take riding lessons from the same lady that helped with our pony at first.
Thank you all for sharing your thoughts and advice.