I think it's whatsmyip.org, not whatsmyip.com. That site will show you the WAN (Wide Area Network) address of your router, not the private LAN address (192.168.blah.blah) of your device. For more info, look up NAT (Network Address Translation). On her iPhone, maybe check that Settings->Wi-Fi->Ask to Join Networks is set to OFF. You can also make sure on this screen that she's connected to your network.