Never criticize the size of another pregnant woman

My cousin and I are very close. I am 28.5 weeks pregnant and her sister in law is a little further along than me. I was over weight before I got pregnant and actually lost 5lbs in my first 6 months of pregnancy. I have since gained those 5lbs back and 3 more. My cousin's sister in law decided yesterday that she was going to tell her how she thought I was huge for how far along I was and that I look way further along than I actually am. Mind you, she was probably 100+ lbs when she got pregnant and has gained nearly 50lbs. My cousin obviously stood up for me but just the fact that she had the nerve to say those things about me made me so mad. 
Being a woman, you should never criticize the size of another woman, especially if you and the other woman are both pregnant.