That must have been so scary! Don't blame yourself too much - you couldn't have known. You did all you could to help her which is all you can expect yourself to do. I've heard people say, horses don't forget, but they often forgive. I'm sure your mare will forgive you - she sounds like a nice little girl.
I guess its a lesson learned for you in how easily an quickly accidents can happen!
When I bestride him, I soar, I am a hawk: he trots the air; the earth sings when he touches it; the basest horn of his hoof is more musical than the pipe of Hermes. ~William Shakespeare