How old is this horse? If she's older than 5, then gray would have definitely made an obvious appearance by this point.
I agree with the concensus that she's either classic roan or expressing sabino roan or maybe a combination of both. The only way to say for certain which it was would be to have her color tested. But, if you don't want to bother with that, you can just call her a blue roan and you would be technically correct.
She's a pretty girl.