iPhone freezes at update requested

Thanks for posting in the Apple Support Communities emrah120,

The following page explains that the time it takes to download an update may vary:

You need an internet connection to update your device. The time it takes to download the update varies according to the size of the update and your internet speed. You can use your device normally while downloading the update, and your device will notify you when you can install it. To improve the speed of the download, avoid downloading other content and use a Wi-Fi network.

You can find this information, as well as additional guidance that may provide a solution, on the following page: If your iPhone or iPad won't update

Cheers!