She knows how to test..without ever doing it..?

I have having a low..and needed my granddaughter to test my sugar (she's. 14) so she got the case and automatically knew what everything was called and what to do..she's never seen anyone test..not even me..she knew just what to do and when I asked how she knew hhow..all she says is" I just it comes naturally" ..no one in her family has ever tested..she dosent have internet..and none of her friends test..I just thought it was strange..do you know how she might of known?