Does anyone know the best way to track child iphone location for free?

My kid is 12 and has been coming home later and later from friend’s houses, and I’m getting worried. I know Find My iPhone exists but I think you need to set it up beforehand - is there any other reliable free app or service that lets me see their location in real-time, even if I didn’t set it up from the start?

There’s no free app that provides real-time tracking without prior setup. Find My iPhone is the main option, but it requires pre-configuration on the device.