A scratch on iPhone 7's (Plus) Touch ID (brand new iphone 7 Plus, picetures)

Hello,

Yesterday I bought my very first iPhone - 7 Plus. Today I noticed a scratch on its Touch ID. It must have been there before i used it. Apple says it's sapphire glass... I don't know if I should return it becouse somehow it works perfectly. The scratch isn't very big, but it is still there. What do you think? Have you noticed something like that on yours? Let me know what you think.