Cute. I like it Emily. I would go with the blue dress. The pink clashes with the red blanket and the green blends with the hill too much for me. Not that any of them are bad I just like the blue the best :)
So fun! I vote for either the blue or pink. I think the blue dress definitely makes her a focal point because it's so different from all the other colors. The pink dress is more cool than the other reds, so it might be a little out of harmony with all the other warm colors. Depending on where you want your focal point, playing around with variations on the pink dress might be the best option if you want the noses to be the main focal point. A agree about the green dress. Too same, same as the grass. So good to see your work!
What about a purple/lavender?
[Something artsy intelligent] Blue dress because it's my favorite.