She's a cute mare but, IMHO, definitely not breeding worthy. Her conformation isn't bad, but its not great either.
The thing that would concern me the most is her temperament. You already said that she was temperamental and very high strung. Even on a prime breeding prospect in every other way, those would be deal breakers for me. I've dealt with enough young horses from "temperamental, high strung" lines and let me tell you, they are a bitch to get them broke enough for anyone less than an expert to safely ride and they are a bitch to keep them sane and calm.
Some light reading that would likely benefit you. Things to think about before you consider breeding.