Why do people mistaken me for my little sisters mother?10 POINTS!?

it happens to me too!!! its b/ cif you are holdiong your sisters hand they think you are the daughter.i was caring my 2 year ol slady adn some lady come up and my and says miss you dropped your babies shoes. she said it in a disguting voice i was so pissed im only 15 and i dont think i loom that old . so i guess just let it slide and if people say what your daughters name tell htem a fake name and act sarcastic happy!!!