Updating from iOS 9 and earlier to iOS 13

Im helping my mother to update her iOS. She hasn’t updated her iPhone 8 since 2018. It’s been 3 hours since the update started and now it seems to be in the endless loop of dark screen and white screen with black Apple logo. The lock screen showed up a couple of times but I couldn’t click any button.

Is it normal to take this long to update? It’s been a few year for sure. Also what are the recommended solutions if there is any?

Thank you so much in advance. My mother never backs up her phone so I’m getting very nervous as time drags on.