IPhone needs me to turn off Find My iPhone but Wi-Fi is disabled on the phone?

Basically I have this old iPhone that I want to reset in case we ever need another phone. But the Wi-Fi is disabled, so I put in an old backup of my iPhone to see if it would fix it, to no fix. So I decided that I would just reset it completely, but now it needs Find My iPhone to be turned off to do so. Well I can't turn it off because Wi-Fi doesn't work and it's not on our wireless account and doesn't have data.

It will need to be connected.

You can erase your iPhone by logging in iCloud official site.