Why is this little girl so mean to me...please answer!?

she's in my ballet cl and she's going to be in 5th grade. i'm going to be in 9th grade. she's in my church, ballet cl and she's fat. she's the pastor's granddaughter. she keeps botherin my lil sis saying rude things and making mean comments of her, making sure my sis doesn't talk to her friends, and other things. today in ballet cl i wore these pants (a href="http://www.abercrombiekids.com/webapp/wcs/stores/servlet/product_10101_10851_349341_-1_12182_12105)" rel="nofollow"http://www.abercrombiekids.com/webapp/wc…/a with this shirt of mine and she looked at me after i changed after ballet cl and said EW! in front of everyone=[ and she doesn't give me any respect. i mean she's the pastor's granddaughter; shouldn't she know better? i hate her and even though it was a lil girl saying it n stuff i get rly offended by those kind of things. no matter whose saying it...my mom says she's just jealous cause she's fat and can't wear stuff like me. everyone kept looking at my pants...is it weird? can anyone cheer me up='[ sorry if i sound mean=/