Instead of app store Google play store is opening in my iPhone 6s plus?

My dad gifted me a new iPhone 6s plus and when I turned it on, it showed the apple logo like any other iPhone shows. But as soon as I opened the app store, I saw that it was actually Google play store. And my phone is unlocking on everyone's finger print. It asked me to sign in with my Google account only. It did not ask me to create a new apple id. And it is a 128 GB device but still showing insufficient storage space while downloading the gangstar Vegas or asphalt 8. The apple logo at the back is gold plated and reflecting. I just want to know whether it is really an iPhone or a fake one. Since this is my first iphone Please help!

Ok, cheers.