My girlfriend wants an unusual thing from me?

okay my girlfriend and i dont have yet (were 18 but i havent felt like stepping forward) but we kiss a lot to make up for it, and we kiss in different places like she likes me to lick food/sweets off her stomach and neck and legs....but she asked me to kiss her feet and lick them and suck them...and i just look at her like shes crazy, she gets mad because shes says that "my girlfriend has really nice and neat feet and that other guys would love to have them" but i dont believe so (about the guys) is it normal to pur your lips on someones feet...and she always trys to encourage me by saying you dont like them they are so small and cute and i moisturize them just for you and i make sure they are nice for you...what am i to do?