My sister and I are both overweight. I am 25 and shes 15. We started trying to lose weight but I have changed my diet started eating less and Less pop. Also in summer walk 3 to 4 miles a day. Now that it's cold I've been going to the gym. I've lost weight and am now 180lbs. Shes gained and at 195lbs. Shes trying to make me feel bad for bettering myself. And I'm wondering should i feel guilty? Please help. This is killing me

Edit >>>>>>>> I should add... I've been trying to help her. She doesn't want to work out at home or the gym, she eats all the time, won't drink water. Sleeps when not at school, will eat whole box of mac and cheese by herself. I have tried telling her what I did and she wont listen but continues to try and bring me down for doing it. I was 245lbs before I started trying to lose weight.