OK. After reviewing the thread, this will not be popular. Oh well!
My first horse was a green broke two year old that our trainer sold us. She was rock solid- carried my mother into the show ring as a three year old. She also carried her into Valley Forge Park for the Bicentennial carrying my mother and the flag. She never thought a bad thought in her entire life. She is buried here. Her foals were just as amazing as she was.
So, my advice? Go with your gut. If she is solid for you, and you trust her, take her. Yes, there are all kinds of reasons- some of which are on here- not to do it. Life offers you all kinds of experiences. You can choose to go for it, or not. If you are uncomfortable with the mare, that’s different. If she is the one who you enjoy being around, and working with, just do it. It’s a relationship. It’s personal. It has to work for you, and only for you.
I have put more rescues- a different thing to be sure- together with people over the years than I can even remember. They worked. You have to want to do this, and put in the work. Changing trainers, looking for a different horse, all of that is possible. But, do you like the mare?
Just my 02.