If you know anything about iPhones, Please

Yesterday I switched from the iPhone 4 to the iPhone 5 because of my upgrade. The one thing I liked about the 5 is that it wasn't updated with iOS 7.So I got home and started getting my new phone they way I wanted it. But when I connected to the Wi-Fi at my house, iOS 7 started downloading and I'm not sure how to stop it. So as of now, my Wi-Fi is off because I really don't want iOS 7. Any comments?

You can disconnect Internet connection and then you can't go on downloading.
I guess the downloading will be stopped and the you can continue only after you resume it.
I do not think it will work by iteself