This is a nicely taken picture; however, how can one tell that this is a miniature stadium? If you had put a full size baseball in the stadium it would have made all the difference - then it would have been instantly obvious that this was a minature stadium.
At first glance this almost looks like a real stadium. There is a lot of noise in the picture. Maybe the ISO setting was high on your camera. I think the composition works well. However there is nothing in the image to give a sense of scale. I can't tell how big or small the subject is.
While I know this is a miniature, my understanding of the challenge was to have a regular sized object to show off the miniature size of the subject. Therefore placing a full size object in the frame would have made this better in my eyes... 6
Doesn't meet the challenge, no frame of reference to determine size. Compose and photograph something "miniature" in such a way that it conveys to the viewer that the subject of your photo is a tinier version of something that is normally larger.