That's a beautiful filly, contentedly flying along like the autumn breeze and enjoying nature (while running off some leaves a bit early perhaps). I love that pretty freckled face and huge, wonder-filled eyes, plus you did a terrific job making her leaping gallop flow as freely and enchantingly as the breeze itself. With the bright fade at the top you made sure our eyes are always drawn back to her, but no matter how I "adjust the contrast" (move up and down relative to my LCD screen) or adjust the histograms I can't tell if the trail is covered or open above. There just seems to be a lot of light coming from everywhere, though I have to admit that it gives her great definition without making her too dark by contrast. (Offsetting with the shadowy bottom-right plus underneath her does balance things out fairly well.) And the "dabs" with the closer tree, speckles of light, and then the freed leaves themselves, it's all gorgeous. The foreshortening and rounded perspective do a great job to convey the sense of speed and distance.
Anyway, she's a beautiful young mare and you've made her exceptionally dynamic and expressive while giving the scene some context. I certainly hope you're accepted into the group. They'd be lucky to have you.
Wow, job VERY well done. The one and only criticism that I have for this is that the trees in the background all melt together into a vast expanse of nothingness. A simple shadow-outline separating the trees from one another would go a long way toward solidifying the background.
That aside, my jaw is getting swore from hitting the floor with all of this art you're uploading!
It isnt the end of the world that the blank space is there. It gives the feeling of sunlight coming through the trees. Again, I just think that it would be a slight detail change that could go a long way toward making this all the better.