First off I think she is gorgeous, and I applaud anyone who can keep a white horse clean!
I wont critique her head/throatlatch area as its mostly covered, so moving down to her neck, I think it needs more muscling, and needs to sit higher upon her chest but the muscling will probably come with more age. One of the characteristics of the breed is that its neck ties in smoothly, in one of your pictures it does, but inthe other it doesnt. Also I am not a fan of her shoulder angle as it is much to steep. Her back is short which I like. She appears to be calf kneed, and very sickle hocked which I don't believe is her breed standard.
But you appear to be doing a good job with her, and she looks pleasant to be around