Quick start needed to update iOS first!

Hello,

i am trying to setting up the new iPhone 11 my mom got last night. We wanted to transfer the data from her iPhone 6s to the new iPhone 11 via Quick start. We began the process just fine, but afterwards, the iPhone 11 prompts us to download new iOS update. Mind you, there is no option to skip or ‘remind me later’ in the prompt screen. So we tapped yes and it began downloading and installing. However it has been more than 12 hours but the iPhone 11 is still trying to update! It is crazy loong. I have been searching through Google etc but could not find any solutions. Is this normal process? What can i do to set up the iPhone? Thank you x